Biomedical subjects

Lawrence M Weiss

Publications and source records attributed to Lawrence M Weiss.

At least 19 recordsLinked to original sources

PubMed2006

Calcifying fibrous tumor of the adrenal gland.

Calcifying fibrous tumor is an uncommon entity with distinctive pathologic features. Most calcifying fibrous tumors involve the peripheral soft tissues or serosal surfaces, with reports of visceral examples of this lesion being extremely limited. We report the clinical and pathologic features of an unusual case of calcifying fibrous tumor occurring in the adrenal gland of a 32-year-old woman. Microscopically, the lesion was well circumscribed and composed of dense, poorly cellular collagenous tissue, scattered spindle cells, an inflammatory infiltrate consisting of plasma cells and lymphocytes, and dystrophic calcifications. The morphologic diagnosis of calcifying fibrous tumor was supported by diffuse positive immunoreactivity for factor XIIIa and absence of reactivity for muscle specific actin, smooth muscle actin, and anaplastic lymphoma kinase. Although rare, awareness that calcifying fibrous tumor may occur at this particular site is important so as not to confuse this lesion with other mesenchymal neoplasms of the adrenal gland.

Adrenal Gland Neoplasms↗

PubMed2006

Prolymphocytoid transformation of follicular lymphoma with coexpression of CD5 and CD10.

Histologic transformation of follicular lymphoma is usually to a diffuse large B-cell lymphoma. We present a rare example of a histologic transformation of follicular lymphoma manifested by prolymphocytoid morphology and an unusual immunophenotype characterized by coexpression of CD5 and CD10. The transformed prolymphocytoid lymphoma was positive for CD5 and CD10 antigens by both flow cytometry and immunohistochemistry. The case also expressed bcl-2 and bcl-6 proteins, and exhibited t(14;18), consistent with derivation from a pre-existing follicular lymphoma. Polymerase chain reaction analysis of the immunoglobulin kappa light chain genes derived from the follicular lymphoma and prolymphocytoid lymphoma showed identical rearranged bands, suggesting clonal identity of the two neoplasms. The basis for coexpression of CD5 and CD10 remains unclear. Because the preceding low-grade follicular lymphoma was positive only for CD10 and did not express CD5, CD5 expression appears to be an acquired phenomenon accompanying the process of histologic transformation in this particular case. Prolymphocytoid transformation, similar to other histologic forms of transformation of follicular lymphoma, appears to accompany clinical progression of disease.

Adult↗

PubMed2006

Hodgkin lymphoma-like posttransplant lymphoproliferative disorder (HL-like PTLD) simulates monomorphic B-cell PTLD both clinically and pathologically.

Although Hodgkin lymphoma-like posttransplantation lymphoproliferative disorder (HL-like PTLD) has been grouped with classic Hodgkin lymphoma type PTLD (HL-PTLD), controversy remains as to whether it is truly a form of HL or whether it should be more appropriately classified as a form of B-cell PTLD. Because only few cases of HL-like PTLD have been reported, their pathologic nature and clinical behavior have not been well defined. This report characterized 5 cases of HL-like PTLD with respect to their immunophenotype, EBV status, clonality, and clinical outcome. All of the patients were male, with ages ranging from 1.5 to 55 years at diagnosis. PTLD developed from 4 months to 6 years following solid organ transplantation (3 hearts, 1 kidney, 1 liver), and involved both nodal and extranodal sites. All were EBV-related (EBER+) with the large neoplastic cells CD20/CD79a positive but CD15 negative. Immunoglobulin gene rearrangements were detected in 3 of 5 tested. All patients were managed by initial reduction/withdrawal of immunosuppression, with 2 also receiving chemotherapy for non-HL. Three patients died of progressive disease within 2 to 3 months after diagnosis, 1 is alive and well 2 years later, and the fifth was disease free but died of unrelated causes (graft coronary disease) 2 years later. We conclude that, although HL-like PTLD morphologically simulates classic HL PTLD, there are important immunophenotypic, molecular genetic, and clinical differences, suggesting it is in fact most often a B-cell PTLD. Distinction between HL and HL-like PTLD may be important for clinical management and prognosis.

Adolescent↗

PubMed2006

Immunohistochemical expression of estrogen receptor in pulmonary adenocarcinoma.

Estrogen receptor (ER) is a useful immunohistochemical marker of breast carcinomas and is commonly used as a means of distinguishing breast carcinomas from adenocarcinomas of other primary sites, including the lung. Previous reports have yielded conflicting data regarding ER immunoreactivity in primary pulmonary adenocarcinomas. In this study the immunohistochemical expression of ER was evaluated in 55 primary lung adenocarcinomas using the 1D5 antibody clone. Immunohistochemistry for thyroid transcription factor-1 (TTF-1), a sensitive and specific marker of pulmonary adenocarcinomas, was also performed. ER expression was observed in 10 (18%) of 55 lung adenocarcinomas. Most of these pulmonary adenocarcinomas showed ER immunoreactivity of weak or moderate intensity (<25% of tumor cell nuclei). However, two cases exhibited strong ER immunoreactivity (51-75% of neoplastic cells). Forty-six (84%) of the 55 lung adenocarcinomas were TTF-1 positive, including all those that expressed ER. These results indicate that a subset of pulmonary adenocarcinomas can exhibit ER immunoreactivity. As such, caution should be exercised in the use of ER immunohistochemistry alone as a means of distinguishing breast carcinomas from lung adenocarcinomas. In the context of an ER-positive lung neoplasm, strong and extensive TTF-1 immunoreactivity can be regarded as strong supportive evidence for a primary bronchogenic adenocarcinoma.

Adenocarcinoma↗

PubMed2006

Sustentaculoma: report of a case of a distinctive neoplasm of the adrenal medulla.

A case of a morphologically distinctive tumor of the adrenal medulla occurring in a 54-year-old woman is described. On microscopic examination, the tumor was well circumscribed and characterized by the presence of ill-defined, irregular nests of spindle cells with oval to elongated nuclei, tiny nucleoli, and abundant eosinophilic cytoplasm. The tumor was associated with a moderate infiltrate of lymphocytes and plasma cells with occasional lymphoid follicles. Necrosis, marked cellular atypia, and mitoses were absent. Immunohistochemical studies demonstrated the tumor cells to be strongly reactive for vimentin, S-100 protein, and CD56, and nonreactive for glial fibrillary acidic protein, chromogranin, synaptophysin, melanoma-associated antigens, and dendritic cell markers. Ultrastructural examination showed elongated cells with interdigitating cytoplasmic processes devoid of a basal lamina. No secretory granules were noted. The morphology, immunophenotype, and ultrastructure of this unique neoplasm suggest derivation from sustentacular cells of the adrenal medulla. We propose the designation "sustentaculoma" for this hitherto undescribed neoplasm of the adrenal gland.

Adrenal Gland Diseases↗

PubMed2006

Schwannoma of the adrenal gland: report of two cases.

Primary schwannomas of the adrenal gland are extremely uncommon. We report the clinical and pathologic features of two cases, occurring in a 73-year-old man and a 26-year-old woman, both of whom presented with abdominal pain and an adrenal mass on imaging studies. Both tumors were characterized by a proliferation of cytologically bland spindle cells. One case exhibited alternating compact Antoni A areas and less cellular Antoni B areas consistent with conventional schwannoma, whereas the other case was hypercellular and composed predominantly of Antoni A areas consistent with cellular schwannoma. Reactive inflammatory cells and lymphoid aggregates were present throughout both tumors. The diagnosis of schwannoma was supported by positive immunoreactivity for S-100 protein and collagen IV and absence of reactivity for keratin, muscle related antigens, and CD34 in both cases. Electron microscopy was also performed in the case of cellular schwannoma, which showed ultrastructural features confirming the diagnosis. Both cases had a favorable outcome without evidence of recurrence or metastasis. Because of its rarity, schwannoma occurring at this particular site can pose problems in diagnosis and should be distinguished from other spindle cell lesions of the adrenal gland.

Adrenal Gland Neoplasms↗

PubMed2006

Extranodal Rosai-Dorfman disease involving the bone marrow: a case report.

Sinus histiocytosis with massive lymphadenopathy (SHML), also known as Rosai-Dorfman disease, is a very rare disorder of unknown etiology. Although classical SHML usually presents as massive, painless, bilateral neck lymph node enlargement, approximately 25% to 40% of SHML cases described to date present in extranodal organs or tissues, such as skin, upper respiratory tract, and bone etc. However, bone marrow as a site of initial presentation by SHML has not been described since the disease was initially recognized in 1969. Here, we report the first case of bone marrow involvement by extranodal SHML, which occured in a 73 year-old man with a history of refractory idiopathic thrombocytopenia purpura. The bone marrow biopsy demonstrates the distinctive and characteristic morphologic and immunophenotypic features of extranodal SHML.

Aged↗

PubMed2006

Lineage determination of CD20- B-Cell neoplasms: an immunohistochemical study.

We studied 61 CD20- B-cell lymphomas, including 29 cases of precursor B-cell lymphoblastic leukemia/lymphoblastic lymphoma (B-ALL/B-LBL), 25 cases of CD20- recurrent mature B-cell lymphoma after rituximab therapy, and 7 cases of CD20- diffuse large B cell lymphoma (DLBCL). We used markers specific for B lineage: CD79a, Pax-5, OCT.2, and BOB.1. All B-ALL/B-LBLs expressed Pax-5 (29/29 [100%]), 25 (93%) of 27 expressed BOB.1, 23 (79%) of 29 expressed CD79a, and 6 (22%) of 27 expressed OCT.2. The percentages of cases expressing Pax-5, CD79a, OCT.2, and BOB.1 in CD20- recurrent mature B-cell lymphomas after rituximab treatment were 88% (21/24), 84% (21/25), 81% (17/21), and 73% (16/22), respectively. CD20- DLBCLs rarely express routine B-lineage markers, such as and CD79a and Pax-5, but they expressed OCT.2 or BOB.1. Pax-5, BOB.1, and CD79a antigens are the most reliable B-lineage markers for paraffin immunophenotyping B-ALL/B-LBL. CD79a and Pax-5 should be used as the first-line B lineage-specific markers for rituximab-treated CD20- mature B-cell lymphomas. If negative, OCT.2 or BOB.1 may be useful. The newly identified B-lineage markers, OCT.2 and BOB.1, may be the most useful for the B-lineage determination of CD20- plasmablastic or primary effusion subtypes of DLBCL.

Antibodies, Monoclonal↗

PubMed2006

Composite recurrent hodgkin lymphoma and diffuse large B-cell lymphoma: one clone, two faces.

We describe a composite lymphoma with recurrent Hodgkin lymphoma and diffuse large B-cell lymphoma components manifesting as a single, perforated small intestinal tumor in a 56-year-old man with a history of classical Hodgkin lymphoma and recent relapse in the bone marrow. The resected mass had 2 morphologically and immunophenotypically distinct components; 1 showed a pleomorphic cellular infiltrate with fibrosis and contained numerous, large Hodgkin/Reed-Sternberg-like cells and variants. The tumor cells were CD30+ and focally positive for CD15 but CD20-, CD79a-, and PAX-5-. In situ hybridization for Epstein-Barr virus (EBV) was strongly positive in the large pleomorphic tumor cells. The adjacent component displayed sheets of relatively uniform, large lymphoid cells with typical morphologic features of diffuse large cell lymphoma. The tumor cells showed uniform expression of tested B-cell antigens, absence of CD30 or CD15, and complete absence of EBV-encoded RNA. Separate molecular studies with immunoglobulin heavy and k light chain gene rearrangements clearly demonstrated an identical rearrangement pattern, indicating derivation from the same clone, which was confirmed by direct DNA sequencing analysis. Such distinctly different morphology, immunophenotype, and EBV status in different components within a clonally related single tumor mass is striking.

Antigens, CD↗

PubMed2005

Lack of association of cytomegalovirus with human brain tumors.

Cytomegalovirus (CMV) is thought to possess oncogenic properties and has been linked with a number of human malignancies. CMV infection was recently described in association with malignant gliomas. The intent of the present study was to further investigate the reported association between CMV and malignant gliomas. Tissue from 22 brain tumors of various histologic types and grades, four normal brains, six breast carcinomas, six colon carcinomas, six lung carcinomas, and six sarcomas were evaluated for the presence of CMV by polymerase chain reaction (PCR), in situ hybridization, and immunohistochemical methods. None of the brain tumors or normal brain tissue tested demonstrated evidence of CMV pp65 or early nuclear proteins by immunohistochemistry. In addition, no CMV RNA or DNA was detected in these cases by in situ hybridization and PCR. None of the carcinomas or sarcomas evaluated were positive for CMV by immunohistochemistry, in situ hybridization, or PCR. The findings of the present study suggest that CMV is not significantly associated with brain tumors in humans.

Brain Neoplasms↗

PubMed2005

T-cell/histiocyte-rich large B-cell lymphoma displays a heterogeneity similar to diffuse large B-cell lymphoma: a clinicopathologic, immunohistochemical, and molecular study of 30 cases.

T-cell/histiocyte-rich large B-cell lymphoma (THRLBCL), a proliferating peripheral B-cell neoplasm, is a morphologic variant of diffuse large B-cell lymphoma (DLBCL), which may be confused with Hodgkin's lymphoma, non-Hodgkin's lymphoma, and reactive lymphadenopathies. Though more recent studies suggested that it might be a distinct clinicopathologic entity and/or a heterogeneous entity with derivation from germinal center B cells, its histogenetic derivation remains controversial. The authors analyzed 30 cases of THRLBCL to further characterize the origin of the neoplastic cells using immunohistochemical and molecular studies for expression of Bcl-6, CD10, and CD138, as well as rearrangements of IgH/bcl-2 genes on paraffin-embedded tissue. Half of the cases (15/30) showed Bcl-6 expression and five cases (19%) showed CD10 expression, but none had CD138 expression (0/20). Only three cases showed coexpression of both Bcl-6 and CD10. Molecular studies performed in 21 cases detected rearrangement of immunoglobulin heavy gene in 18 cases, with none having detectable Bcl-2 gene rearrangement. These data indicate that similar to DLBCL, the cell origin of neoplastic cells in THRLBCL is composed of a heterogeneous group of proliferating peripheral B cells, with only some cases originating from germinal center B cells and others derived from heterogeneous origins. Lack of Bcl-2 gene rearrangements seems to argue against a possible progression from preexisting follicular lymphoma. Thus, the normal counterpart of the neoplastic cells cannot at this time be the sole basis for the subclassification of THRLBCL.

Adolescent↗

PubMed2005

Immunohistochemical staining in the diagnosis of pancreatobiliary and ampulla of Vater adenocarcinoma: application of CDX2, CK17, MUC1, and MUC2.

Pancreatobiliary and ampulla of Vater adenocarcinomas frequently metastasize to regional lymph nodes, liver, or lung and are difficult to diagnose because they lack specific immunohistochemical markers. We studied the expression of cytokeratin 7 (CK7), cytokeratin 17 (CK17), cytokeratin 20 (CK20), CDX2, mucin 1 (MUC1), mucin 2 (MUC2), and mucin 5AC (MUC5AC) in 46 cases of pancreatic ductal carcinoma, 18 ampulla of Vater adenocarcinomas, and 24 intrahepatic cholangiocarcinomas. The expression of MUC1 and CK17 was restricted to pancreatic ductal carcinoma (41 of 46, 89%; 38 of 46, 83%, respectively), the ampullary carcinoma of pancreatobiliary origin (6 of 6, 100%; 5 of 6, 83%, respectively), and intrahepatic cholangiocarcinoma (20 of 24, 83%; 17 of 24, 71%, respectively). More than 50% of cases of pancreatobiliary adenocarcinomas showed diffuse cytoplasmic CK17 positivity. In contrast, less than 5% cases (8 of 184) of extra-pancreatobiliary nonmucinous adenocarcinomas expressed CK17, and only 3 of them showed diffuse CK17 positivity. The expression of MUC2 and CDX2 was restricted to the intestinal, mucinous, and signet-ring cell-type adenocarcinomas of duodenal papillary origin (9 of 11, 82%; 11 of 11, 100%, respectively). MUC2 was rarely expressed in pancreatic ductal carcinoma (1 of 46, 2%) and was negative in the ampullary carcinoma of pancreatobiliary origin and in intrahepatic cholangiocarcinoma. A heterogeneous CDX2 staining pattern was seen in 1 of 6 cases of the ampullary carcinoma of pancreatobiliary origin (17%), 5 of 24 intrahepatic cholangiocarcinomas (21%), and 10 of 46 (22%) pancreatic ductal carcinomas. In contrast, all 11 cases of the intestinal, mucinous, and signet-ring cell-type adenocarcinomas of duodenal papillary origin showed homogeneous CDX2 nuclear positivity. We concluded that CK17 is a useful marker in separating pancreatobiliary adenocarcinomas from extra-pancreatobiliary nonmucinous adenocarcinomas, including adenocarcinomas from the colon, breast, gynecologic organs, stomach, lung, prostate, thyroid, kidney, and adrenal gland, and malignant mesothelioma. MUC1+/CK17+ can be used as positive markers for pancreatic ductal carcinomas, the ampullary carcinoma of pancreatobiliary origin, and cholangiocarcinomas with positive predictive values of 76%, 83%, and 58%, respectively. MUC2+/CDX2+ can be used as positive markers for the intestinal-type adenocarcinoma of duodenal papillary origin with a positive predictive value of 82%.

Adenocarcinoma↗

PubMed2005

Incidental and concurrent malignant lymphomas discovered at the time of prostatectomy and prostate biopsy: a study of 29 cases.

The incidence and histologic features of malignant lymphomas discovered at the time of prostate biopsy, transurethral resection, and prostatectomy are not well documented. We searched our surgical pathology files for malignant lymphomas identified from prostate surgical specimens from 1989 to 2004. Of 4,831 cases of prostate specimens (3,405 biopsies, 266 transurethral resections, 1,160 prostatectomies) examined at the City of Hope during this period, 29 cases of malignant lymphomas involving the prostate and pelvic lymph nodes were identified (0.6%). These malignant lymphomas can be divided into two groups: 1) 18 incidental cases (0.37%) without prior history of malignant lymphoma; and 2) 11 cases (0.23%) with concurrent known malignant lymphoma. For the first group, the patients with pelvic node involvement ranged in age from 59 to 78 years (mean, 69.2 years; median, 70 years), and the patients with prostate involvement ranged in age from 45 to 78 years (mean, 64.6 years; median, 67.5 years). For the second group, the patients ranged in age from 53 to 80 years (mean, 66.8 years; median, 69 years). Diagnoses of all cases were confirmed by immunohistochemistry or molecular analysis. Ten of 18 cases in the first group involved pelvic nodes only, and the other 8 cases were primary prostatic lymphoma. Of 18 cases in the first group, 13 were small lymphocytic lymphoma/chronic lymphocytic leukemia (SLL/CLL), 3 were marginal zone B-cell lymphoma, and 1 was mantle cell lymphoma. These lymphomas were not readily apparent in most cases by histologic examination, and may be confused with chronic prostatitis when the prostate was involved or with reactive lymphoid hyperplasia when pelvic nodes were involved. Immunohistochemistry and molecular studies may be necessary to confirm the diagnosis. For the second group, prostate and pelvic lymph nodes were involved as part of systemic dissemination of concurrent malignant lymphoma. The diagnosis was usually easily established in these cases. Of 11 cases, 4 were SLL/CLL, 4 were follicular lymphoma, 2 were mantle cell lymphoma, and 1 was diffuse large B-cell lymphoma.

Aged↗

PubMed2005

An aggressive extranodal NK-cell lymphoma arising from indolent NK-cell lymphoproliferative disorder.

Indolent NK-cell lymphoproliferative disorder, also known as chronic natural killer (NK) cell large granular lymphocytosis (leukemia), is a very rare entity in the World Health Organization (WHO) Classification of Tumors of Hematopoietic & Lymphoid Tissues. Unlike aggressive NK-cell leukemia, which is malignant, the WHO does not specify whether indolent NK-cell lymphoproliferative disorder is reactive or neoplastic. Patients with indolent NK-cell lymphoproliferative disorder are usually asymptomatic older adults who have a nonprogressive, very stable clinical course. We report an unusual case of an aggressive extranodal NK-cell lymphoma, non-nasal type, which presented as a subcutaneous tissue mass, which apparently transformed from a preexisting, untreated indolent NK-cell lymphoproliferative disorder in an 65-year-old otherwise healthy white man. The extranodal NK-cell lymphoma and the NK-cell lymphoproliferative disorder in the blood and bone marrow share a distinctive and identical NK-cell immunophenotype and genotype: CD56/CD8/TIA-1-positive and surface CD3-negative, negative for Epstein-Barr virus infection, and no evidence of T-cell and B-cell receptor gene rearrangements. To the best of our knowledge, such aggressive lymphomatous transformation in an indolent NK-cell lymphoproliferative disorder has not been previously reported.

Aged↗

PubMed2005

Primary diffuse large B-cell lymphoma of the uterus presenting solely as an endometrial polyp.

We report a primary diffuse large B-cell lymphoma of endometrial polyp in a 44-year-old woman who presented with irregular vaginal spotting and was found to have a polyp protruding from the cervical os. Histology of the polyp showed an atypical diffuse infiltration by large, mononuclear cells within the stroma and between endometrial glands in one of the polypoid fragments. Immunohistochemistry and testing for immunoglobulin heavy chain gene rearrangement showed a B-cell lineage, consistent with diffuse large B-cell lymphoma. Staging procedures including detailed gynecology examination, body computed tomography scan, and bone marrow examination, as well as total hysterectomy, showed no evidence of lymphoma outside of the polyp. To our knowledge, this represents the first well-documented instance of primary lymphoma of the uterus presenting as an endometrial polyp. The differential diagnosis of endometrial biopsies containing an atypical lymphoid infiltrate should include the rather rare possibility of primary uterine lymphoma arising in an endometrial polyp. Immunohistochemistry and/or molecular analysis for antigen receptor gene rearrangements are critical in arriving at the correct diagnosis.

Adult↗

PubMed2004

Urothelial carcinoma of the urinary bladder with a component of acinar/tubular type differentiation simulating prostatic adenocarcinoma.

We report a case of an 83-year-old man with a high-grade carcinoma of the urinary bladder who underwent cystoprostatectomy. The invasive carcinoma showed mixed, morphologically distinct patterns consisting of conventional high-grade urothelial carcinoma, glandular differentiation resembling enteric type adenocarcinoma, and acinar/tubular type differentiation, morphologically similar to Gleason grade 3 prostatic adenocarcinoma. Immunohistochemical studies revealed the acinar/tubular component of the tumor to be negative for prostate-specific antigen and prostatic acid phosphatase, but positive for cytokeratin 7, cytokeratin 20, high molecular weight cytokeratin (34 beta E12), and thrombomodulin, consistent with origin from the bladder rather than the prostate. Although bladder carcinomas composed of mixed morphologic patterns are not uncommon, to our knowledge, the presence of acinar/tubular type features simulating prostatic adenocarcinoma in such tumors has not been described elsewhere.

Adenocarcinoma↗

PubMed2004

Epstein-Barr virus plays no role in the tumorigenesis of small-cell carcinoma of the lung.

Epstein-Barr virus infection has been associated with lymphoepithelioma-like carcinoma of the lung in Asian patients. Recently, Epstein-Barr virus proteins or genomic DNAs were detected in pulmonary squamous-cell carcinoma, adenocarcinoma, and undifferentiated small-cell carcinoma in American patients. We studied 23 cases of small-cell carcinoma of the lung for evidence of Epstein-Barr virus infection by in situ hybridization, immunohistochemistry, and polymerase chain reaction methods. Of the 23 cases, 13 cases were primary small-cell carcinoma of the lung and 10 cases were metastatic small-cell carcinoma of the lung to the brain (one case), liver (two cases), and lymph nodes (seven cases). None of the 23 cases was positive for Epstein-Barr virus-encoded small nonpolyadenylated RNA (EBER)-1 by in situ hybridization. By immunohistochemistry, eight cases showed focal positivity for Epstein-Barr virus nuclear antigen-1. The positive immunostaining was focal and was observed in tumor cells, vascular endothelial cells, and lymphocytes, suggesting nonspecific staining. None of the 23 cases was positive for the transactivating immediate-early BZLF1 (ZEBRA) and latent membrane protein (LMP-1). Only one case was positive for the BamHI W region and LMP-1 gene by polymerase chain reaction assay. Some tumor cells in the BamHI W region positive case were also positive for Epstein-Barr virus nuclear antigen-1. Our study indicates that rare cases of American small-cell carcinoma of the lung may contain Epstein-Barr virus-infected cells, but it is unlikely that Epstein-Barr virus plays a role in the tumorigenesis of small-cell carcinoma of the lung.

Biomarkers, Tumor↗

PubMed2004

Intraneural synovial sarcoma: two cases.

We report two cases of intraneural synovial sarcoma. The first patient is a 46-year-old female who presented for several months with soft-tissue mass in the right infra-auricular region. The second patient is a 11-year-old girl who fell and then presented with pain in the area innervated by the right C7 spinal root and a nodule identified in the nerve root foramina. Both lesions were of small size and presented with features of synovial sarcoma. A biphasic variant was found in case 1 and a monophasic variant was present in case 2. Immunohistochemical studies were performed to confirm the diagnosis, excluding the main differential diagnoses, namely schwannoma and malignant peripheral nerve sheath tumor. Ultrastructural study was performed in case 2 allowing exclusion of other possible diagnoses. Molecular studies were performed on paraffin-embedded tissue in both cases and revealed the known characteristic t(X;18)(SYT-SSX) translocation.

Child↗