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Biomedical subjects

Martin J Trotter

Publications and source records attributed to Martin J Trotter.

5 recordsLinked to original sources

Atypical fibroxanthoma with prominent sclerosis.

BACKGROUND: Malignant cutaneous spindle cell lesions with marked sclerosis are uncommon. Only a few cases of cutaneous leiomyosarcoma and dermatofibrosarcoma protuberans with sclerosis have been published. METHODS: We report a case of atypical fibroxanthoma (AFX) with prominent sclerosis and hyalinization occurring on the scalp of an 81-year-old male. RESULTS: Histopathologic examination revealed an exophytic, well-delineated, focally ulcerated tumor arising in sun-damaged skin. The lesion was composed of atypical spindle cells arranged in a fascicled and vaguely storiform pattern. Occasional multinucleated giant cells were present. The tumor cells were strongly positive for CD99 (O13), vimentin, and smooth muscle actin, and focally positive for CD68. There was striking sclerosis with hyalinization throughout the lesion. CONCLUSIONS: Rarely, AFX may exhibit marked sclerosis with areas of complete replacement of tumor by hyalinized collagen. In a small biopsy, such hyalinization may be a diagnostic pitfall leading to an erroneous diagnosis.

Aged↗

Are en face frozen sections accurate for diagnosing margin status in melanocytic lesions?

To assess the diagnostic accuracy of margin evaluation of melanocytic lesions using en face frozen sections compared with standard paraffin-embedded sections, we studied 2 sets of lesions in which en face frozen sections were used for analysis of surgical margins (13 from malignant melanomas [MMs] and 10 from nonmelanocytic lesions [NMLs]). Routine permanent sections were cut after routine processing. The slides were mixed and coded randomly. Fifteen dermatopathologists examined the cases separately. Margin status was categorized as positive, negative, or indeterminate. Kappa statistics were calculated per dermatopathologist and per case. One case from each group was excluded because epidermis was not available in the routine sections. Of 330 evaluations (22 cases, 15 dermatopathologists), there were 132 diagnostic discrepancies (40.0%): 66 each for MM and NML (mean per case for both diagnoses, 6). In 9 instances (6.8%), the change was from positive (frozen) to negative (permanent) and in 43 (32.6%), from negative (frozen) to positive (permanent). There was poor agreement between frozen and permanent sections (kappa range per dermatopathologist, -0.1282 to 0.6615). If permanent histology is considered the "gold standard" for histologic evaluation, en face frozen sections are not suitable for accurate surgical margin assessment of melanocytic lesions.

Aged↗

Treatment of cutaneous melanoma of the face by Mohs micrographic surgery.

BACKGROUND: The treatment of cutaneous malignant melanoma of the face presents a challenge to ensure eradication of disease with maximum preservation of tissue. Mohs micrographic surgery provides a means for histologically controlled removal of malignant melanoma. OBJECTIVE: This study evaluates the efficacy of Mohs micrographic surgery, at a single institution, for the treatment of facial melanoma and assesses the accuracy of margin control by frozen section techniques. METHODS: Ninety-seven patients with biopsy-confirmed melanoma in situ or invasive melanoma of the face were treated by Mohs micrographic surgery over a 6-year period. In 25 patients, tissue margins defined as negative for melanoma at the time of frozen section were re-evaluated on permanent section histology of formalin-fixed, paraffin-embedded tissue. RESULTS: Ninety-two of 97 patients had followup information available (8-72 months; mean 33 months). There were no cases of local recurrence. Eighty-nine of the 92 patients were alive and well with no evidence of disease. One patient died of metastatic melanoma. In situ or invasive melanoma was not identified on permanent sections of 117 tissue margins which had been interpreted as negative on frozen section. CONCLUSION: Mohs micrographic surgery appears to be an effective treatment for facial melanomas. Our study showed complete correlation between frozen section tissue margins and permanent section controls.

Adult↗

Expression of desmin and smooth muscle myosin heavy chain in dermatofibromas.

BACKGROUND: The histopathologic features of dermatofibroma vary remarkably, and this diversity may occasionally cause problems in differentiating between benign and malignant mesenchymal lesions, including smooth muscle neoplasms. Immunohistochemical stains are sometimes necessary to clarify the histogenesis of a lesion. OBJECTIVE: To evaluate dermatofibromas for expression of desmin and smooth muscle myosin heavy chain (SM-MHC) antigens, which are commonly used as evidence of smooth muscle differentiation. METHODS: We studied 100 consecutive cases of dermatofibroma using hematoxylin-eosin-stained sections and immunoperoxidase staining with antibodies against desmin, SM-MHC, and smooth muscle actin. RESULTS: We found focal positivity for desmin in 9 cases, and in 2 of these cases, at least 10% of lesional cells showed strong expression. We found focal staining for SM-MHC in 10 cases, and in 2 of these cases, at least 10% of the lesional cells were positive. Regions positive for desmin and/or SM-MHC did not show definite histologic features of myogenous differentiation on hematoxylin-eosin-stained sections. All dermatofibromas expressing desmin and SM-MHC were also strongly positive for smooth muscle actin. CONCLUSIONS: About 10% of dermatofibromas show focal expression of desmin and SM-MHC, and this expression may be present in up to 10% to 15% of lesional cells. Thus, in dermal spindle cell lesions, focal expression of these muscle antigens, like that of smooth muscle actin, is not diagnostic of a smooth muscle tumor.

Actins↗