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Andrew L Folpe

Publications and source records attributed to Andrew L Folpe.

At least 19 recordsLinked to original sources

Well-differentiated fetal adenocarcinoma of the lung: cytomorphologic features on fine-needle aspiration with emphasis on use of beta-catenin as a useful diagnostic marker.

Well-differentiated fetal adenocarcinoma (WDFA), also known as low grade adenocarcinoma of the fetal lung type, is a rare pulmonary neoplasm now considered to be a variant of lung adenocarcinoma rather than a type of pulmonary blastoma. Upregulation of the Wnt signaling pathway with subsequent aberrant nuclear/cytoplasmic beta-catenin expression has been recently described in these tumors providing a possible pathogenetic role for this gene in WDFA. We describe the cytomorphologic findings of a case of WDFA in a 36-yr-old female patient and emphasize the diagnostic utility of aberrant nuclear/cytoplasmic expression of beta-catenin as an adjunct to the correct preoperative recognition of this tumor on aspiration cytology.

Adenocarcinoma↗

Heterotopic mesenteric ossification: a distinctive pseudosarcoma commonly associated with intestinal obstruction.

Heterotopic mesenteric ossification (HMO) is a rare intraabdominal bone-producing pseudosarcoma with fewer than 14 reported cases in the literature. We report our experience with 6 additional cases, all of which were referred to us with a diagnostic consideration of extraskeletal osteosarcoma (EO) or "sarcoma" and emphasize features which distinguish HMO from EO. Six intraabdominal lesions coded as "heterotopic mesenteric ossification," "ossifying pseudotumor," or "reactive myofibroblastic proliferation with ossification" were retrieved from our consultation files. Clinical follow-up information was obtained. Lesions occurred exclusively in males, with a mean patient age of 49 years (range, 22-72 years). The tumors occurred in the mesentery (N = 4), omentum (N = 1), or both (N = 1) and were preceded by significant abdominal surgery (4 cases) or trauma (1 case) in all but 1 case. Five patients presented with bowel obstruction and 1 with abdominal sepsis. Tumors were difficult to precisely measure; the mean size of the resection specimens was 11.8 cm (range, 3.5-20 cm). Grossly, the tumors resembled fat necrosis and often cut with a gritty sensation. Microscopically, all lesions demonstrated an exuberant, reactive (myo)fibroblastic proliferation resembling nodular fasciitis, with extensive hemorrhage and fat necrosis. All tumors produced abundant bone and osteoid, often "lace-like," and 2 contained cartilage. The proliferating (myo)fibroblasts, osteoblasts, and chondroblasts were mitotically active but cytologically bland. Follow-up (4 cases; mean, 47.3 months; range, 5-120 months) showed 3 patients alive without disease and 1 dead of unrelated causes. One case was recent. HMO is a distinct intraabdominal ossifying pseudotumor that typically occurs in males, almost always after surgery or abdominal trauma, and frequently presents with symptoms of intestinal obstruction. This clinical history, presence of clearly reactive zones resembling nodular fasciitis, thick osteoid, and absence of nuclear atypia, necrosis, and atypical mitotic figures allow the distinction of HMO from its most important morphologic mimic, EO.

Adult↗

Alveolar soft-part sarcoma of the urinary bladder with urethral recurrence: a unique case with emphasis on differential diagnoses and diagnostic utility of an immunohistochemical panel including TFE3.

Alveolar soft-part sarcoma (ASPS) is a rare, clinically, morphologically, ultrastructurally, and cytogenetically distinctive malignant mesenchymal tumor that most classically occurs in the extremities of adolescents and young adults, but has also been described in a number of unusual sites. The molecular signature of ASPS is a specific der(17)t(X;17)(p11.2;q25) translocation, which results in the fusion of TFE3 transcription factor gene (from Xp11) with ASPL at 17q25. The ASPL-TFE3 fusion protein encoded by the fusion transcript can be detected immunohistochemically with commercially available antibodies to the carboxy terminus of TFE3. Herein, we report a unique case of ASPS presenting in the bladder with subsequent urethral recurrence in a 25-year-old woman. We emphasize the differential diagnoses engendered by ASPS including common, not-so-common, and rare tumors involving the urinary bladder that have a nested architecture, and both clear and eosinophilic cytoplasm, and demonstrate the utility of a broad immunohistochemistry panel including TFE3 for diagnosis.

Adult↗

Epithelioid hemangioendothelioma of the oral cavity: report of two cases and review of the literature.

The epithelioid hemangioendothelioma is an uncommon vascular neoplasm of borderline or intermediate malignant potential. Although numerous sites of involvement are possible, these tumors most commonly arise in soft tissue, liver, and lung. Involvement of the oral cavity is rare. Only 12 cases of intraoral epithelioid hemangioendothelioma have been reported in the English language literature. We review the salient features of these previously reported cases and present 2 additional intraoral cases--one presenting as an asymptomatic radiolucency in the posterior mandible of a 23-year-old female, and the other presenting as an asymptomatic, erythematous to purplish gingival nodule in a 28-year-old female. Intraoral tumors most commonly involve the gingival soft tissues and often are associated with adjacent alveolar bone resorption. Although it is not possible to estimate with accuracy the potential for recurrence and metastasis among intraoral tumors given the small number of previously reported cases, wide local excision with close clinical follow-up appears to be the treatment of choice for these tumors because of their unpredictable clinical behavior.

Adult↗

Latency-associated nuclear antigen expression and human herpesvirus-8 polymerase chain reaction in the evaluation of Kaposi sarcoma and other vascular tumors in HIV-positive patients.

Human herpesvirus-8 (HHV-8) latency-associated nuclear antigen (LANA) is expressed in endothelial and spindle cells of nearly all Kaposi sarcomas, and the presence of this antigen in serum is strongly correlated with the risk of developing Kaposi sarcoma in immunocompromised individuals. Studies of vascular tumors occurring in the general population show LANA expression to be specific for Kaposi sarcoma. No study to date, however, has examined whether non-Kaposi sarcoma vascular tumors arising in immunocompromised patients may express LANA, possibly reflecting origin from an HHV-8-infected endothelial progenitor cell. The objective of this study was to evaluate the specificity of LANA expression for Kaposi sarcoma in immunocompromised patients by LANA immunohistochemistry and real-time polymerase chain reaction (PCR) for HHV-8. A total of 13 cases of non-Kaposi sarcoma vascular tumors (12 hemangiomas and one epithelioid hemangioendothelioma) and 24 cases of Kaposi sarcoma, all from known HIV-positive patients, were immunostained for LANA and evaluated for the presence of HHV-8 DNA by real-time PCR. LANA expression was seen in 22 of 24 (92%) of Kaposi sarcoma cases and in 0 of 13 non-Kaposi sarcoma cases. Real-time PCR detected HHV-8 in all of the Kaposi sarcoma cases and in four of the non-Kaposi sarcoma cases (all hemangiomas). LANA expression appears to be a highly sensitive and specific marker of Kaposi sarcoma in both the general population and in HIV-positive patients. This is in contrast to HHV-8 PCR, which is positive in a small subset of non-Kaposi sarcoma vascular tumors, most likely due to detection of HHV-8 within intratumoral blood mononuclear cells by the highly sensitive real-time PCR technique. For this reason, LANA immunohistochemistry is preferable to HHV-8 PCR for the evaluation of problematic vascular proliferations in HIV-positive individuals.

Adult↗

Intercellular junctions in Ewing sarcoma/primitive neuroectodermal tumor: additional evidence of epithelial differentiation.

Ewing sarcoma/primitive neuroectodermal tumor (ES/PNET) has recently been shown to frequently express cytokeratins, suggesting partial epithelial differentiation. Older ultrastructural studies have documented primitive cell-cell junctions in ES/PNET, reportedly resembling poorly formed desmosomes. Recently, paraffin-reactive antibodies have become available to proteins found in a variety of intercellular junctions indicative of epithelial differentiation, including tight junctions, desmosomes and adherens junctions. We examined intercellular junction protein expression in a large number of genetically confirmed ES/PNET. Formalin-fixed, paraffin-embedded sections from 23 primary and seven recurrent or metastatic cases of genetically confirmed ES/PNET were immunostained for claudin-1 and occludin (tight junction structural proteins), zonula occludens-1 (ZO-1, tight junction linker protein), desmoglein 1/2 (desmosomal adherens protein), desmoplakin (desmosomal structural protein) and E-cadherin (epithelial adherens junction protein), using steam heat-induced epitope retrieval and the Dako Envision system. Cases with >5% positive cells were scored as 'positive'. Normal colonic epithelium and skin served as external positive controls. Claudin-1 was expressed by 19 of 30 specimens (63%), ZO-1 was expressed by 15 of 29 specimens (51%), and occludin was expressed by three of 28 specimens (11%). In 28 specimens all three tight junction markers were evaluable. In all, 15 samples (54%) expressed only one tight junction marker, and 10 samples (36%) expressed two tight junction markers. No case expressed all three tight junction markers. Desmoglein was expressed in one of 30 (3%) samples. Desmoplakin was expressed in two of 28 (7%) samples. E-cadherin was negative in all cases. Our data suggest that many of the previously described cell-cell junctions in ES/PNET are poorly formed tight junctions, given the high frequency of claudin-1 and ZO-1 expression. This may underestimate the true frequency of tight junction protein expression in ES/PNET, as there are at least 20 different claudins and other ZO proteins. These tight junctions are almost certainly abnormal, given the absence of occludin expression in most cases. Desmosomal and adherens junction protein expression was rare to absent. Our findings provide additional evidence that ES/PNET frequently show partial epithelial differentiation.

Bone Neoplasms↗

Dual-color, break-apart fluorescence in situ hybridization for EWS gene rearrangement distinguishes clear cell sarcoma of soft tissue from malignant melanoma.

Clear cell sarcoma of soft tissue (malignant melanoma of soft parts) is a soft tissue sarcoma with melanocytic differentiation that typically occurs in the tendons and aponeuroses of young adults. As demonstrated by cytogenetics and reverse-transcriptase polymerase chain reaction, between 70% and over 90% of clear cell sarcomas have a t(12;22) translocation, fusing the EWS and ATF1 genes on chromosomes 22q12 and 12q13, respectively. Identification of this translocation distinguishes clear cell sarcoma from histologic mimics, most importantly conventional malignant melanoma. We report our experience with a commercially available, dual-color, break-apart fluorescence in situ hybridization (FISH) probe, which allows detection of EWS (22q12) gene rearrangement in formalin-fixed, paraffin-embedded tissues. Histologically and immunophenotypically well-characterized cases of clear cell sarcoma (n = 10) and malignant melanoma (n = 32) were evaluated with a 22q12 dual-color, break-apart probe (Vysis, Downer's Grove, IL, USA), which spans the known common breakpoints in the EWS gene on chromosome 22 (introns 7-10). Signals from tumor cell nuclei were counted under a fluorescence microscope and the presence of red-green break-apart signals was recorded. Of the clear cell sarcoma cases, seven of 10 showed evidence of an EWS gene rearrangement with a mean of 81.6% positive cells per sample (range: 60-95%). All cases of malignant melanoma (n = 32) showed virtually absent break-apart signals in the EWS gene (less than 4% cells per case). FISH detects EWS gene rearrangement in a substantial proportion of clear cell sarcomas, with excellent specificity. Importantly, EWS FISH is negative in malignant melanoma, a clinically dissimilar tumor, which may closely mimic clear cell sarcoma histologically and immunohistochemically. As the studied probe can be utilized in routinely processed tissue, FISH provides an excellent alternative to reverse-transcriptase polymerase chain reaction in cases where fresh tissue is unavailable.

Diagnosis, Differential↗

The diagnostic value of beta-catenin immunohistochemistry.

beta-catenin is a 92-kDa protein that binds to the cytoplasmic tail of E-cadherin. It acts in the nucleus to stimulate cell proliferation and is degraded by complexing with the adenomatous polyposis coli gene. When it is mutated, it is ineffectively degraded and results in unchecked proliferative activity that plays a role in a subset of neoplasms. When there are alterations in beta-catenin degradation, it accumulates to a sufficient extent to be detected in the nuclei of tumor cells immunohistochemically, a feature that can be exploited in the differential diagnosis of selected neoplasms. Immunohistochemistry for beta-catenin may be useful in the differential diagnosis of selected tumors of soft tissue, the gastrointestinal tract, including the pancreas, lung, and female genital tract.

Biomarkers, Tumor↗

Distribution of cytokeratins and vimentin in adult renal neoplasms and normal renal tissue: potential utility of a cytokeratin antibody panel in the differential diagnosis of renal tumors.

Adult renal epithelial neoplasms (RENs) comprise several distinct clinicopathologic entities with potential prognostic and therapeutic differences. Individual cases can show overlapping morphologic features, necessitating the use of ancillary methods. The purpose of this study was to determine the diagnostic utility of cytokeratin (CK) subtype expression pattern in a wide range of adult RENs. RENs (including clear cell [conventional] renal cell carcinoma (RCC), papillary RCC, chromophobe RCC, renal oncocytoma, collecting duct carcinoma (CDC), renal medullary carcinoma (RMC), urothelial carcinoma, metanephric adenoma (MA), tubulocystic carcinoma (TC) (also known as low-grade collecting duct carcinoma), and mucinous tubular and spindle cell carcinoma) were immunostained for CK subtypes (CK5/CK6, 7, 8, 13, 14, 17, 18, 19, 20), high molecular weight CKs 1, 5, 10, 14 (HMWCK), and vimentin (Vim). The expression pattern of normal kidney was also examined and correlated with RENs. Although there is some overlap, subtypes of RENs show distinctive CK expression profiles that may be useful in several differential diagnostic settings. Clear cell RCCs typically showed a restricted expression pattern of CK8, CK18 and Vim. Papillary RCCs typically expressed CK7, CK8, CK18, CK19, and Vim and could be distinguished from MA (CK7-). Chromophobe RCCs were typically CK7+, CK8+, CK18+, and Vim-, and could be distinguished from oncocytomas (typically CK7-). In oncocytomas, nonspecific staining of unblocked endogenous biotin is a potentially significant diagnostic pitfall. CDC, RMC, and TC demonstrated similar CK expression profiles (with the exception of HMWCK expression limited to CDC), supporting a close relationship between these entities. A panel of CK5/CK6, CK17, and Vim may be helpful in distinguishing CDC (typically CK5/CK6-, CK17-, Vim+) and urothelial carcinoma (typically CK5/CK6+, CK17+, Vim-). In conclusion, CK expression patterns may be helpful in several differential diagnostic situations when dealing with adult RENs.

Adult↗

Perivascular epithelioid cell neoplasms of soft tissue and gynecologic origin: a clinicopathologic study of 26 cases and review of the literature.

PEComas, occasionally associated with the tuberous sclerosis complex, are defined by the presence of perivascular epithelioid cells that coexpress muscle and melanocytic markers. This family of tumors includes angiomyolipoma (AML), clear cell sugar tumor of the lung (CCST), lymphangioleiomyomatosis (LAM), and very rare tumors in other locations. Because non-AML/non-LAM PEComas are extremely rare and their natural history and prognostic features undefined, we present our experience with 26 PEComas of soft tissue and the gynecologic tract, the largest series to date. We also performed a detailed review of the literature, with special attention to features predictive of clinical behavior. All PEComas exclusive of AML and LAM were retrieved from our consultation files. Immunohistochemistry for pan-cytokeratin (CK), S-100 protein, smooth muscle actins (SMA), desmin, vimentin, HMB45, Melan-A, microphthalmia transcription factor (MiTF), TFE3, CD117, and CD34 was performed. Clinical follow-up information was obtained. Fisher's exact test was performed. The median patient age was 46 years (range, 15-97 years); there was a marked female predominance (22 females, 4 males). Sites of involvement included the omentum or mesentery (6 cases), uterus (4 cases), pelvic soft tissues (3 cases), abdominal wall (2 cases), uterine cervix (2 cases), and vagina, retroperitoneum, thigh, falciform ligament, scalp, broad ligament, forearm, shoulder, and neck (1 case each). The tumors ranged from 1.6 to 29 cm in size (median, 7.8 cm). Tumors were epithelioid (N = 9), spindled (N = 7), or mixed (N = 10). Multinucleated giant cells were present in 18 cases. High nuclear grade was noted in 10 cases, high cellularity in 7 cases, necrosis in 8 cases, and vascular invasion in 3 cases. Mitotic activity was 0 to 50 mitotic figures (MF)/50 high power fields (HPF) (median, 0 MF/50 HPF) with atypical MF in 6 cases. IHC results were: SMA (20/25), desmin (8/22), HMB45 (22/24), Melan-A (13/18), MITF (9/18), S-100 protein (8/24), CK (3/23), vimentin (12/14), TFE3 (5/17), c-kit (1/20), and CD34 (0/7). Clinical follow-up (24 of 26 patients, 92%; median, 30 months; range, 10-84 months) showed 3 local recurrences and 5 distant metastases. At last available clinical follow-up, 2 patients (8%) were dead of disease, 4 patients (17%) were alive with metastatic or unresectable local disease, and 18 patients (75%) were alive with no evidence of disease. No patient in our series had a history of tuberous sclerosis complex. Recurrence and/or metastasis was strongly associated tumor size > median size (8 cm), mitotic activity greater than 1/50 HPF, and necrosis. We conclude that PEComas of soft tissue and gynecologic origin may be classified as "benign," "of uncertain malignant potential," or "malignant." Small PEComas without any worrisome histologic features are most likely benign. PEComas with nuclear pleomorphism alone ("symplastic") and large PEComas without other worrisome features have uncertain malignant potential. PEComas with two or more worrisome histologic features should be considered malignant. Occasional PEComas express unusual markers, such as S-100 protein, desmin, and rarely CK. The role of TFE3 in PEComas should be further studied.

Adolescent↗

Morphologic and immunophenotypic diversity in Ewing family tumors: a study of 66 genetically confirmed cases.

More than 85% of Ewing sarcoma/primitive neuroectodermal tumor (ES/PNET), or "Ewing family of tumors" (EFTs), have the translocation, t (11;22) (q24;q12), with others having variant translocations. Identification of these by cytogenetic and/or molecular genetic techniques is specific for EFT and is increasingly recognized as the "gold standard" for diagnosis. However, these techniques are not universally available. We therefore studied a large group of genetically confirmed EFTs to more completely understand the morphologic and immunophenotypic spectrum of this rare sarcoma. Sixty-six cytogenetically, FISH or RT-PCR proven-EFTs were retrieved. In 56 cases, immunohistochemistry (IHC) was performed for pan-cytokeratins (PanCK), high molecular weight cytokeratins (HMWCK), desmin (DES), CD99, CD117, and FLI1 protein using heat-induced epitope retrieval and the Dako Envision system. The cases arose chiefly in children and young adults (median 18 years; range, 3-65 years) of both sexes (male, 32; female, 31; unknown, 3) in a variety of bone (N = 39) and soft tissue (N = 27) sites. Histologically, 46 cases (73%) showed only typical features of ES, 9 cases (16%) showed features of PNET, 3 cases (5%) showed "adamantinoma-like" features, 3 cases (5%) corresponded to "atypical Ewing sarcoma," 3 cases (5%) showed principally intersecting fascicles of spindled cells, and 2 cases had abundant hyalinized matrix. IHC results were as follows: PanCK (18 of 56, 32%), HMWCK (3 of 55, 5%), DES (1 of 56, 2%), CD99 (52 of 52, 100%), CD117 (13 of 54, 24%), and FLI1 (44 of 47, 94%). HMWCK was expressed only in "adamantinoma-like" EFTs, none of which expressed DES. In conclusion, most, but not all, EFTs can be accurately diagnosed using time-honored morphologic criteria and ancillary immunohistochemistry. However, genetic confirmation remains essential for the diagnosis of unusual morphologic variants of EFT, including "adamantinoma-like," spindled, sclerosing, and clear cell/anaplastic variants. Therefore, to exclude or confirm the diagnosis of Ewing's sarcoma in round cell sarcomas having a variety of patterns but not specifically conforming to a tumor of known lineage (eg, rhabdomyosarcoma), cytogenetics, and/or molecular analysis is required.

12E7 Antigen↗

Aberrant expression of tight junction-related proteins ZO-1, claudin-1 and occludin in synovial sarcoma: an immunohistochemical study with ultrastructural correlation.

Synovial sarcoma demonstrates epithelial differentiation, either by light microscopy (biphasic synovial sarcoma) or by immunohistochemical/ultrastructural methods only (monophasic) and poorly differentiated synovial sarcoma. Although the glands of synovial sarcoma are known to have tight junction-like structures, far less is known about junction formation in the spindled component of synovial sarcomas. Additionally, it is unknown whether the tight junctions of synovial sarcoma are normally constituted. The tight junction is a multiprotein complex consisting of numerous proteins that include ZO-1, claudin-1 and occludin. A total of 35 cases of synovial sarcoma (13 biphasic, 14 monophasic and eight poorly differentiated) were immunostained for ZO-1, claudin-1 and occludin using commercially available antibodies, heat-induced epitope retrieval and standard avidin-biotin technique. When available, corresponding electron micrographs were reviewed. For five cases, the presence of either an SYT-SSX1 (three cases) or SYT-SSX2 (two cases) gene fusion was known. Positive cases showed particulate membrane staining. The glands of biphasic synovial sarcomas expressed ZO-1 (13/13), claudin-1 (12/13) and occludin (11/13) in a manner identical to normal glandular epithelia, at the apical portion of the lateral membrane. The spindle cells of biphasic synovial sarcomas showed abnormal circumferential membranous expression of ZO-1 (12/13), claudin-1 (6/13) and occludin (3/13). Monophasic synovial sarcomas expressed ZO-1 in a circumferential pattern (13/14) but less often claudin-1 (4/14) or occludin (3/14). Poorly differentiated synovial sarcomas expressed ZO-1 (8/8) and claudin-1 (6/8) but only rarely occludin (2/8). By electron microscopy, recognizable tight junctions were seen only in glands. No correlation was seen between histologic subtype or fusion type and expression of tight junction proteins. We conclude that the glands of biphasic synovial sarcomas show well-organized, true epithelial tight junctions. In contrast, the spindled cells of all synovial sarcomas show significant abnormalities in the expression and localization of tight junction proteins, suggesting partial and/or aberrant epithelial differentiation.

Claudin-1↗

Cutaneous and subcutaneous fibrohistiocytic tumors of intermediate malignancy: an update.

The fibrohistiocytic tumors of intermediate malignancy are uncommon mesenchymal tumors, which typically occur in the skin and subcutis and which may pose significant problems for the dermatopathologist. This article reviews the clinical, histopathologic, and genetic features of dermatofibrosarcoma protuberans, giant cell fibroblastoma, angiomatoid (malignant) fibrous histiocytoma, plexiform fibrous histiocytoma, and soft tissue giant cell tumor (of low malignant potential). The differential diagnosis of these tumors with a variety of benign and fully malignant cutaneous soft tissue neoplasms is discussed.

DNA, Neoplasm↗

Most osteomalacia-associated mesenchymal tumors are a single histopathologic entity: an analysis of 32 cases and a comprehensive review of the literature.

Oncogenic osteomalacia (OO) is a rare paraneoplastic syndrome of osteomalacia due to phosphate wasting. The phosphaturic mesenchymal tumor (mixed connective tissue variant) (PMTMCT) is an extremely rare, distinctive tumor that is frequently associated with OO. Despite its association with OO, many PMTMCTs go unrecognized because they are erroneously diagnosed as other mesenchymal tumors. Expression of fibroblast growth factor-23 (FGF-23), a recently described protein putatively implicated in renal tubular phosphate loss, has been shown in a small number of mesenchymal tumors with known OO. The clinicopathological features of 32 mesenchymal tumors either with known OO (29) or with features suggestive of PMTMCT (3) were studied. Immunohistochemistry for cytokeratin, S-100, actin, desmin, CD34, and FGF-23 was performed. The patients (13 male, 19 female) ranged from 9 to 80 years in age (median 53 years). A long history of OO was common. The cases had been originally diagnosed as PMTMCT (15), hemangiopericytoma (HPC) (3), osteosarcoma (3), giant cell tumor (2), and other (9). The tumors occurred in a variety of soft tissue (21) and bone sites (11) and ranged from 1.7 to 14 cm. Twenty-four cases were classic PMTMCT with low cellularity, myxoid change, bland spindled cells, distinctive "grungy" calcified matrix, fat, HPC-like vessels, microcysts, hemorrhage, osteoclasts, and an incomplete rim of membranous ossification. Four of these benign-appearing PMTMCTs contained osteoid-like matrix. Three other PMTMCTs were hypercellular and cytologically atypical and were considered malignant. The 3 cases without known OO were histologically identical to the typical PMTMCT. Four cases did not resemble PMTMCT: 2 sinonasal HPC, 1 conventional HPC, and 1 sclerosing osteosarcoma. Three cases expressed actin; all other markers were negative. Expression of FGF-23 was seen in 17 of 21 cases by immunohistochemistry and in 2 of 2 cases by RT-PCR. Follow-up (25 cases, 6-348 months) indicated the following: 21 alive with no evidence of disease and with normal serum chemistry, 4 alive with disease (1 malignant PMTMCT with lung metastases). We conclude that most cases of mesenchymal tumor-associated OO, both in the present series and in the reported literature, are due to PMTMCT. Improved recognition of their histologic spectrum, including the presence of bone or osteoid-like matrix in otherwise typical cases and the existence of malignant forms, should allow distinction from other mesenchymal tumors. Recognition of PMTMCT is critical, as complete resection cures intractable OO. Immunohistochemistry and RT-PCR for FGF-23 confirm the role of this protein in PMTMCT-associated OO.

Adolescent↗

Kaposiform hemangioendothelioma: a study of 33 cases emphasizing its pathologic, immunophenotypic, and biologic uniqueness from juvenile hemangioma.

Kaposiform hemangioendothelioma (KH) is a rare tumor of childhood often associated with Kasabach-Merritt phenomenon (KMP) and occasionally lymphangiomatosis. Although generally considered distinct from other vascular neoplasms, its rarity has precluded a thorough study of its immunophenotypic profile and long-term behavior. Thirty-three cases of KH were reviewed and immunostained for alpha-smooth muscle actin, various endothelial markers (CD31, CD34, vWf, FLI1), a platelet marker (CD61), and the juvenile hemangioma-associated markers GLUT-1 and Lewis Y antigen (LeY). In addition, the presence of HHV-8 was evaluated by RT-PCR. The patients (20 males and 13 females) ranged in age from 2 weeks to 20 years (mean 3 years 9 months). Tumors developed on the extremities (17 cases), head/neck (8 cases), and other sites (8 cases) and affected both superficial and deep soft tissue. Those in the skin presented as slightly raised blue-red lesions. More than half of the patients presented with KMP (14 of 25). Tumors consisted of irregular, infiltrating nodules of compressed vessels, which modulated between areas resembling a capillary hemangioma and Kaposi sarcoma (KS). Endothelial cells in nodules were CD31, CD34, and FLI1 positive but negative for GLUT1 and LeY. Scattered "epithelioid" or glomeruloid islands featuring endothelium associated with clusters of plump alpha-smooth muscle actin-positive pericytes, stippled hemosiderin, and CD61-positive fibrin thrombi likely represent the morphologic sites of platelet consumption. Small and large lymphatic channels occurred in 22 of 33 cases and were typically seen peripheral or deep to the main tumor mass. HHV-8 transcripts were not identified (0 of 3 cases). Follow-up information was available in 22 patients (range 8 months to 15 years; mean 2 years) and indicated that 3 died of disease, 8 were alive with disease, and 10 were alive without residual disease. Two patients developed regional perinodal soft tissue involvement, but none developed distant metastases. KH is a lesion having both a vascular and lymphatic component. Its common association with KMP probably relates in part to unique architectural features that favor turbulent blood flow and platelet activation. KH can also be reliably separated from JH by GLUT-1 and LeY immunostaining, indicating differences in the morphologic and functional attributes of the endothelium between the two lesions. The absence of HHV-8 in KH underscores a different pathogenesis from Kaposi sarcoma. Our study, the largest to date, emphasizes that mortality is due to KMP and not metastatic disease, which appears limited to regional perinodal soft tissue. Given this behavior, its continued classification as a vascular tumor of intermediate malignancy is warranted.

Adolescent↗

CDX-2, a new marker for adenocarcinoma of gastrointestinal origin.

CDX2-88 is a recently developed monoclonal antibody to the intestinal epithelia-specific nuclear transcription factor CDX2. CDX2 immunohistochemistry has recently been shown to be useful in establishing gastrointestinal origin in metastatic tumors and will likely become a useful addition to the standard panel of immunostains for carcinomas of unknown primary sites. This article reviews the previous studies of this new antibody.

Adenocarcinoma↗

Cutaneous angiosarcoma following breast-conserving surgery and radiation: an analysis of 27 cases.

Iatrogenic angiosarcomas (AS), following treatment of breast carcinomas and attributed to chronic lymphedema, were first described by Stewart and Treves. With emphasis on breast-conserving therapy combined with adjuvant radiation, a recently recognized form of cutaneous postradiation angiosarcoma of the breast (CPRASB) has emerged. To more completely characterize CPRASB, 27 cases were analyzed. Histologic features studied included pattern of growth (vasoformative, sieve-like, or solid), nuclear grade, necrosis, and mitotic rate. Clinical and follow-up information was obtained. The patients received relatively standard radiation treatment. The median interval to diagnosis of CPRASB was 59 months; 5 occurred in less than 3 years. Lymphedema was largely absent, and when present was only mild in nature. CPRASB was frequently multifocal at presentation (13 of 27). All tumors had a vasoformative pattern of growth; the majority (16 of 27) had areas with a sieve-like pattern. The solid pattern was less frequent (7 of 27). The majority had high-grade nuclear features (16 grade 3, 8 grade 2, 3 grade1). The mean mitotic rate was 9/10 HPF. Necrosis was rare (2 of 27). All were treated with wide excision or mastectomy. Follow-up was available on 22 of 27 cases (median 44 months). Fourteen experienced local recurrence and 6 had multiple recurrences. Metastasis was documented in 9 of 22 patients and involved lungs (6), contralateral breast (3), skeleton (2), lymph nodes (1), and soft tissue (1). Eight patients died of disease, 2 died with disease, 4 were alive with disease, and 8 are alive without disease. The median interval to death was 33.5 months. All 4 patients with disease have documented metastasis. CPRASB differs from Stewart-Treves AS by its shorter latency period and lack of association with lymphedema.

Aged↗