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PubMed1992

Psychogenic seizures: ictal characteristics and diagnostic pitfalls.

We analyzed ictal features of psychogenic seizures using video-EEG recordings in 47 patients and reviewed the medical records to determine if patients received antiepileptic drug therapy and whether they were treated pharmacologically for status epilepticus. Unresponsive behavior in the absence of motor manifestations was the single most common ictal presentation. Motor characteristics previously considered to distinguish psychogenic seizures (out-of-phase limb movements, side-to-side head movements, pelvic thrusting) were infrequent. Most patients (74%) received anticonvulsants, and six were treated as status epilepticus. Slow, subtle writhing or in-phase limb movements were most likely to be mistaken for status epilepticus. Physicians, assuming that the spells constituted a neurologic emergency, omitted the neurologic examination and chart review and proceeded with aggressive pharmacotherapy based merely on observation.

Adolescent↗
PubMed2005

Changing phenotype of gastrointestinal stromal tumours under imatinib mesylate treatment: a potential diagnostic pitfall.

AIMS: The diagnosis of gastrointesinal stromal tumours (GISTs) is widely based on morphological features and KIT (CD117) immunoreactivity. Most patients with advanced GISTs show a major clinical response after treatment with imatinib mesylate. The histopathological features of GISTs in patients on prolonged imatinib treatment have, thus far, not been addressed in detail. In this report, we present three patients with metastatic GISTs, who received more than 1 year of therapy with imatinib, and whose tumours changed their morphological and immunohistochemical characteristics during continued treatment with the drug. METHODS AND RESULTS: All three primary GISTs from these patients were classical spindle-type tumours, showing diffuse, strong CD117, CD34, and focal alpha-smooth muscle actin expression. During treatment, two clinically progressive and one clinically stable GIST revealed a diffuse epithelioid, or pseudopapillary epithelioid growth pattern, characterized by rounded cells with eosinophilic cytoplasm and uniform round-to-ovoid nuclei. In addition, GIST specimens from patients on therapy showed complete loss of CD117 immunoreactivity. Remarkably, two of these tumours also became CD34 immunonegative and in one case the progression was accompanied by desmin expression. KIT mutational analysis revealed the presence of distinct exon 11 mutant isoforms in all cases examined, while the same genotype was sustained in the base line and on-therapy tumour specimens, proving the common origin of analysed specimens. CONCLUSIONS: GISTs subject to imatinib treatment can undergo striking (immuno)phenotypic changes, which are not necessarily corroborated by new genotypic modifications. Because these may mimic other tumour types, this feature creates a differential diagnostic challenge, of which the pathologist should be aware.

Actins↗
PubMed2005

Cytologic features and diagnostic pitfalls of primary ampullary tumors by endoscopic ultrasound-guided fine-needle aspiration biopsy.

BACKGROUND: Endoscopic ultrasound-guided fine-needle aspiration biopsy (EUS-guided FNAB) is highly sensitive and specific in cytologic diagnosis and clinical staging of malignant neoplasms of the gastrointestinal tract, pancreas, liver, and lymph nodes. However, no study has been performed to evaluate its accuracy, sensitivity, specificity, and the cytomorphologic features of suspected primary ampullary tumors. METHODS: All EUS-guided FNABs of suspected primary ampullary lesions at the University of California Irvine Medical Center (Orange, CA) from January 1998 to September 2004 were retrospectively retrieved. The number of passes necessary to arrive at a preliminary diagnosis during adequacy assessment was documented. The cytologic features were analyzed with endosonographic correlation. Follow-up information was also collected. RESULTS: Thirty-five patients were found, 17 men and 18 women. The mean age of the patients was 68.9 years (range, 34-87 yrs). Adenocarcinoma was diagnosed in 13 patients. Atypical cells were found in six patients, four of which were suspicious for adenocarcinoma and two of which were consistent with reactive atypia. Adenoma was diagnosed in two patients and carcinoid tumor in one. Thirteen patients had a diagnosis that was negative for malignant cells. The average number of aspiration passes was 2.4 (range, 1-6 passes). Follow-up information was available in 27 patients. There were three false-negative results and no false-positive results. The sensitivity, specificity, and the positive and the negative predictive values were 82.4%, 100%, 100%, and 76.9%, respectively. The diagnostic accuracy was 88.8%. The consistent cytologic features in specimens that were positive or suspicious for adenocarcinoma included high cellularity, single cells, 3-dimensional cell balls, high nuclear-to-cytoplasmic ratio, prominent nucleoli, coarse/uneven distribution of chromatin, and necrosis. CONCLUSIONS: EUS-guided FNAB was accurate, sensitive, and specific in the assessment of suspected primary ampullary masses. Adenoma presented a diagnostic challenge and endosonographic correlation was instrumental to increase the diagnostic accuracy.

Adenocarcinoma↗
PubMed2000

Mesothelial hyperplasia with reactive atypia: diagnostic pitfalls and role of immunohistochemical studies-a case report.

The cytomorphologic features of highly reactive mesothelial cells can be difficult to distinguish from malignant cells. We report on an unusual case of mesothelial hyperplasia in a pericardial effusion. The specimen contained bizarre-shaped cells and large tissue fragments in a patient with a history of lung carcinoma. The atypical cells were negative for CEA and LeuM-1 and positive for cytokeratins (AE1/3) and HBME-1. Strong HBME-1 positivity supported a mesothelial origin of the atypical cells and led to the diagnosis of reactive mesothelium. While HBME-1 cannot be used as the sole marker to establish an mesothelial origin; its use in a immunohistochemistry panel may be useful in individual cases to distinguish reactive mesothelial cells from carcinoma in effusion cytology. Diagn. Cytopathol. 2000;22:113-116.

Adenocarcinoma↗
PubMed1995

Increased signal in the normal supraspinatus tendon on MR imaging: diagnostic pitfall caused by the magic-angle effect.

OBJECTIVE: Increased signal intensity within the distal portion of the supraspinatus tendon during MR imaging is a frequent observation even in healthy subjects. This finding has been variously attributed to the presence of fat, muscle, connective tissue, abnormal vascularity, or degenerative changes. More recently, the effect of tendon orientation in the static magnetic field (Bo) has been implicated. It has been shown that tendons at the magic angle of 55 degrees to Bo show markedly increased signal. This study was designed to determine the contribution of the magic-angle effect to the MR signal in the distal portion of the supraspinatus tendon. SUBJECTS AND METHODS: Five healthy volunteers were imaged in a 1.5-T unit using short TR/TE sequences in standard supine position; they were then reimaged laterally flexed at the waist to reorient the plane of the distal portion of the supraspinatus tendon by approximately 20 degrees relative to Bo. In the second part of the study, three cadaveric shoulders were similarly imaged, first in standard position and then reoriented approximately 35 degrees by simple rotation of the specimen. The supraspinatus tendon was evaluated in each subject by noting the length of the segment with increased signal and the position of this segment relative to the insertion of the tendon on the greater tuberosity. Comparisons were made for each live and cadaveric subject between neutral and rotated positions. RESULTS: Segments of increased signal changed in length and position for each live and cadaveric subject from the neutral to the reoriented position. CONCLUSION: Our study suggests that tendon orientation contributes significantly to the presence of increased signal within the supraspinatus tendon, as caused by the magic-angle effect. Failure to recognize this effect may lead to diagnostic inaccuracy when evaluating the rotator cuff on short TR/TE sequences.

Adult↗
PubMed2007

Fine-needle aspiration cytology of basal cell adenoma of the parotid gland: characteristic cytological features and diagnostic pitfalls.

We retrospectively studied the cytological features of aspiration cytology in 12 cases of basal cell adenoma (BCA) and 5 cases mistakenly diagnosed as BCA. On macroscopic findings, the 12 cases of BCA included 7 cases of solid type and 5 cases of cystic type. The characteristic cytological features of solid type BCA were three-dimensional clusters in 71%, sharp-angle small clusters in 86%, basement membrane- like material in 71%, and cell crush in 86%. In contrast, 3 of the 5 cystic type BCA cases showed inadequate cellular components or no basaloid tumor cells, and the cytological diagnosis of BCA could not be determined. In the 5 cases misdiagnosed as BCA, there were 2 cases of pleomorphic adenoma, 2 cases of benign lymphoepithelial cyst, and 1 case of basal cell adenocarcinoma. Accurate differential cytological diagnosis of BCA is relatively easy to determine the solid type BCA, but is more difficult for cystic type BCA.

Adenoma↗
PubMed2005

Nodular fasciitis of the hand: a potential diagnostic pitfall in fine-needle aspiration cytopathology.

Fine-needle aspiration biopsy (FNAB) is applied very uncommonly to soft tissue masses and even more infrequently to lesions of the hand. Nodular fasciitis, an uncommon pseudosarcomatous lesion of soft tissue, rarely occurs in the hand and, because of this, is not often considered in the differential diagnosis of hand masses. We report 3 cases (2 men and 1 woman; mean age, 44.3 years) of soft tissue masses of the hand, which, after clinical and radiologic evaluation, were strongly suspected by an experienced orthopedic oncologist as harboring a soft tissue sarcoma. Each patient underwent FNAB, which showed markedly hypercellular smears with overlapping, relatively isomorphic spindle cells that were mistaken cytologically as possible sarcoma in 2 cases; 1 case was considered probable nodular fasciitis. All lesions eventually were diagnosed as nodular fasciitis after thorough histologic and immunohistologic evaluation. Nodular fasciitis remains a difficult diagnosis by FNAB, particularly when it occurs in locations such as the hand.

Adult↗
PubMed1996

Liver neoplasms: diagnostic pitfalls in cross-sectional imaging.

The appearances of most common liver neoplasms at computed tomography (CT) and magnetic resonance (MR) imaging have been established. However, there are considerable overlaps in the appearances of various pathologic entities. Certain hepatic lesions, such as hepatic hemangioma, adenoma, focal nodular hyperplasia, intrahepatic cholangiocarcinoma, metastases, hepatocellular carcinoma, regenerative nodules, adenomatous hyperplastic nodules, abscess, and hepatocellular carcinoma treated with transcatheter arterial chemoembolization, can have unusual characteristics at CT and MR imaging that may lead to misinterpretation. Dynamic helical CT and double-phase multisection dynamic MR imaging techniques may be helpful in differentiating between these entities because hemodynamics of the lesion can be evaluated by obtaining both arterial-phase and delayed-phase images. It is important for radiologists to be aware of these uncommon appearances of liver neoplasms. Familiarity with these varied CT and MR imaging features will permit a more accurate diagnosis and aid in avoidance of a false diagnosis.

Diagnosis, Differential↗
PubMed2004

Ductal carcinoma in situ with spindle cells: a potential diagnostic pitfall in the evaluation of breast lesions.

AIMS: To evaluate the morphological features of 11 cases of breast ductal carcinoma in situ (DCIS) with spindle cells and to propose an approach to distinguish it from benign mimics. The association with neuroendocrine differentiation was also investigated. METHODS: Cases of breast DCIS with a spindle cell component diagnosed in the Department of Pathology, Singapore General Hospital, between June 1996 and January 2003, were included in the study. The histological characteristics were documented, and immunohistochemistry for neuroendocrine markers, hormone receptors, cerbB2, smooth muscle actin (SMA) and high-molecular-weight (HMW) cytokeratins, was carried out. Electron microscopy was carried out on reprocessed paraffin-embedded material in three cases. RESULTS: Of 11 women diagnosed with DCIS with spindle cells, four presented with nipple discharge, six with a breast lump, while one was discovered to have a screen detected density. The tumour size ranged from 3 to 41 mm. The proportion of spindle cells varied from 10% to 80% of the in-situ tumour cell population. Nuclear grade was low in seven cases and intermediate in four. Necrosis was observed in two cases. Architectural pattern was papillary in six cases, and mixed in the rest. Microinvasion was present in two cases, with possible microinvasion in another two. Immunohistochemistry for neuroendocrine markers synaptophysin and chromogranin showed positive reactivity for at least one marker in all but three cases; one of these latter cases demonstrated ultrastructural neurosecretory granules. Oestrogen and progesterone receptors were expressed in 10 and nine cases, respectively, while cerbB2 was positive in only one case. HMW cytokeratin immunoprofile revealed a general lack of immunostaining within the abnormal cell population; likewise, no positivity for SMA of the cellular proliferation was detected. CONCLUSIONS: Almost all DCIS lesions with spindle cells disclose neuroendocrine differentiation. Although the distinction from benign florid usual hyperplasia may pose a diagnostic histological problem, the presence of diffuse neuroendocrine expression, in conjunction with the pattern of HMW keratin profile on immunohistochemistry, supports an in-situ neoplastic process. The absence of SMA immunostaining, in conjunction with negative reactivity for cytokeratins 5/6 and 14, makes the possibility of a myoepithelial proliferation unlikely.

Aged↗
PubMed1994

Cytomegalovirus sialadenitis in patients with the acquired immunodeficiency syndrome: a potential diagnostic pitfall with fine-needle aspiration cytology.

We report three cases of cytomegalovirus (CMV) sialadenitis which presented as parotid gland nodules in patients infected with the human immunodeficiency virus. While CMV is known to widely infect patients with the acquired immunodeficiency syndrome (AIDS), we are aware of only a single report of CMV sialadenitis in a patient with AIDS (Pialoux et al.: Rev Infect Dis 1991;13:338). Utilizing fine-needle aspiration (FNA) cytology as the initial investigative modality, two cases were correctly diagnosed preoperatively while the third case displayed atypical features and was interpreted erroneously as carcinoma leading to surgical intervention. Upon review of these cases of CMV sialadenitis, the characteristic intranuclear inclusions are best identified with Papanicolaou (Pap) staining. CMV sialadenitis should be considered in the differential diagnosis of painless salivary gland enlargement in patients with AIDS. We believe this lesion can be diagnosed preoperatively with FNA and the interpretation is aided by evaluating both Pap- and Giemsa-stained material.

AIDS-Related Opportunistic Infections↗
PubMed2000

Plasma creatinine assessment in creatine deficiency: A diagnostic pitfall.

Guanidinoacetate methyltransferase (GAMT) deficiency (creatine deficiency syndrome) is a recently discovered inborn error of creatine biosynthesis. Affected patients have elevated concentrations of guanidino-acetate, the metabolic precursor of creatine, in urine, plasma and cerebrospinal fluid. In addition, urinary creatinine excretion and plasma creatinine concentration are decreased. For biochemical evaluation of patients suspected to suffer from GAMT deficiency, correct quantification of creatinine in plasma is important. Here we report our experience with different quantification techniques. We found that creatinine in plasma from two GAMT-deficient patients appeared normal when measured by the Jaffé method but was decreased when measured enzymatically or by HPLC. The apparently normal levels of creatinine as measured by the Jaffé method were not caused by guanidinoacetate. In urine, the Jaffé method and the enzymatic method gave similar results, indicating that in urine no false elevations of creatinine can be expected. As the Jaffé method is still widely used for routine plasma creatinine measurements, it is important to realize it cannot be used to exclude GAMT deficiency.

Creatinine↗
PubMed1999

DNA ploidy in seminal vesicle cells. A potential diagnostic pitfall in urine cytology.

OBJECTIVE: To verify that abnormal DNA ploidy in urine cytology can occasionally be attributed to contamination by seminal vesicle cells. STUDY DESIGN: In the first part of this study, we analyzed the DNA content of six urine cytology specimens containing seminal vesicle cells. In the second part, we evaluated 21 Feulgen-stained prostate core biopsies containing seminal vesicle-type epithelium using a CAS-200 system. DNA index, proliferative activity (S + G2M) and degree of hyperploidy (> 5C) were determined in each case. RESULTS: All six urine cytology specimens were diploid, with all but one containing hyperploid cells (range, 0-16%; mean, 6.3%). Seminal vesicle cells from prostate biopsies showed a broad range of ploidy abnormalities. Ten cases (48%) showed an aneuploid peak, two cases (9%) showed a tetraploid peak, and nine cases (43%) showed only a diploid peak. All but one case showed both an elevation in proliferative activity (mean S + G2M, 24.2%) and some hyperploid cells (mean, > 5C; 4.5%). CONCLUSION: Seminal vesicle cells, although rarely seen in urine cytology, can cause abnormal DNA ploidy measurements. Morphologic criteria remain vital to an accurate cytologic diagnosis.

Aged↗
PubMed2004

Intraductal papilloma with "comedo-like" necrosis, a diagnostic pitfall.

Necrosis in the breast is more frequently associated with malignancies than benign conditions. In the latter, it may be diffuse as seen in infarcts, postpartum changes, and after anticoagulant therapy, or focal as in florid adenosis and juvenile papillomatosis. The goal of this study was to find other benign entities associated with necrosis. Using our pathology database from January 1994 to March 2003, we identified 10 cases of florid duct hyperplasia associated with luminal necrosis. Clinical information was collected and all slides were reviewed. The age of the patients ranged from 36 to 94 years (mean, 53.2 years). All patients underwent an initial excisional biopsy except for one who had a core biopsy. Patients presented with a palpable mass (6 cases) a radiographic density (3 cases), or nipple discharge (1 case). Findings correlated with the presence of an intraductal papilloma with adjacent or associated florid duct hyperplasia. Within the central luminal spaces of the florid duct hyperplasia, cellular debris associated with necrosis was present and was morphologically identical to that seen in comedo intraductal carcinoma. In fact, in two of the four consultation cases, these lesions were initially diagnosed as comedo carcinoma. Re-excision performed in three cases showed no atypia or malignancy. It is important to recognize the presence of comedo-like necrosis in florid duct hyperplasia associated with or adjacent to intraductal papillomas of the breast and not to misinterpret these findings as intraductal carcinoma. The necrosis may be secondary to reactive changes within the intraductal papilloma.

Adult↗
PubMed1996

Desmoplastic malignant melanoma of the oral mucosa. An underrecognized diagnostic pitfall.

BACKGROUND: Although cutaneous desmoplastic malignant melanoma (DMM) has been well characterized, those arising from the oral mucosa have been less well defined. METHODS: We evaluated the clinical and pathologic features of three patients with biopsy-proven DMM examined at the North Carolina Baptist Hospital. Routine hematoxylin and eosin-stained slides were reviewed in all three cases. Sections from all cases were examined immunohistochemically using the avidin-biotin-peroxidase (ABC) technique and employing commercially available antibodies to the following antigens: S-100 protein, HMB-45, NK1C3, and cytokeratin (AE1/AE3). Appropriate positive and negative controls were utilized throughout these procedures. Clinical data were obtained from the patients' medical records. RESULTS: Age at diagnosis for the three male patients were 42, 64, and 75 years. Anatomically, these neoplasms arose from the left maxillary oral mucosa (two patients) and the vermilion border of the lower lip (one patient). Initial incisional biopsies of all three patients were misinterpreted as desmoid tumor (one patient) and squamous cell carcinoma (two patients), respectively. Histologically, all tumors were poorly circumscribed and composed of fascicles and bundles of spindle-shaped cells with hyperchromatic nuclei and associated with extensive stromal collagenization. Perineural invasion was noted in two tumors. An overlying atypical, intraepidermal melanocytic proliferation was observed in two tumors. Immunohistochemically, all three tumors showed positive immunoreactivity with S-100 protein and vimentin. One tumor also expressed HMB-45. Wide surgical incision was the primary mode of therapy in all patients. One patient also received multiple courses of radiation therapy and chemotherapy. One patient died of widespread metastatic disease. CONCLUSIONS: DMM of the oral mucosa is a rare, often unrecognized, form of malignant melanoma associated with a fibrosarcoma-like morphologic appearance and abundant collagenization. Meticulous attention to histomorphology and judicious use of immunohistochemical stains will help prevent misdiagnosis.

Adult↗