bromochloroacetic-acid and Neurofibroma

Merkel cells are an integral component of the cutaneous nervous system. They are commonly associated with dermal nerves under normal physiological conditions. We postulated that Merkel cells may be present in increased numbers within the epidermis overlying benign peripheral nerve sheath tumours such as neurilemomas and neurofibromas. Paraffin-embedded skin biopsy specimens from 21 patients with neurilemomas and 26 with neurofibromas, were analysed for the presence of Merkel cells using a standard immunohistochemical assay (avidin-biotin-peroxidase complex system) with an antibody to cytokeratin 8 (CAM 5.2). Ten cases of leiomyomas were examined as controls. Merkel cells were identified in the interfollicular area of the basal cell layer overlying 14 of 21 (67%) neurilemomas and nine of 26 (35%) neurofibromas. Merkel cells were more frequently observed in increased numbers in a linear array within the basal cell layer in neurilemomas than in neurofibromas, where they were found as individual cells. No Merkel cells were found in the epidermis overlying leiomyomas. The results of this study suggest that Merkel cells are quantitatively increased in the basal cell layer of the epidermis overlying benign peripheral nerve sheath tumours, particularly neurilemomas.

Topics: Humans; Keratins; Neurilemmoma; Neurofibroma; Skin; Skin Neoplasms

Sixty-three pure mesenchymal tumors of the uterus were studied to explore the value of immunostaining in the diagnosis of unusual mesenchymal tumors encountered in the uterus, some not reported previously. Each tumor was evaluated using a panel of immunostains including actin, desmin, vimentin, S-100 protein, and cytokeratin. The final classification, which incorporated the immunohistochemical findings, resulted in the identification of 33 relatively common pure mesenchymal tumors (13 benign and malignant endometrial stromal tumors and 20 benign and malignant smooth muscle tumors) and 30 uncommon tumors (five leiomyosarcomas with osteoclastic giant cells, two xanthomatous leiomyosarcomas, one melanotic schwannoma, one pure rhabdomyosarcoma, one neurofibroma, five plexiform tumorlets, and 15 combined smooth muscle-stromal tumors). The normal endometrial stroma, present in 14 cases, invariably showed a negative reaction for all antibodies. With rare exceptions, the pure endometrial stromal tumors displayed a negative immunoreaction for all antibodies utilized, while the pure smooth muscle tumors consistently showed a positive reaction for actin. Only the two tumors of neural origin (a neurofibroma and a melanotic schwannoma) reacted with S-100 protein. Immunostaining influenced most the final classification of neoplasms initially interpreted as uterine tumors with a sex-cord stromal pattern, endometrial stromal tumors that diverged from the classic lesions by having a spindle cell component, and intravascular leiomyomas with areas of compact proliferation of small round cells with prominent vascularity. All tumors in these three groups were reclassified as combined smooth muscle-stromal tumors following immunohistochemical studies.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Actins; Aged; Aged, 80 and over; Child, Preschool; Desmin; Female; Humans; Immunohistochemistry; Keratins; Leiomyosarcoma; Mesenchymoma; Middle Aged; Neurilemmoma; Neurofibroma; Rhabdomyosarcoma; S100 Proteins; Uterine Neoplasms; Vimentin

Formalin-fixed, paraffin-embedded sections of 59 ultrastructurally confirmed nerve sheath tumors (NSTs) that included 27 benign schwannomas, five neurofibromas, and 27 malignant schwannomas were studied by the avidin-biotin-peroxidase complex method using antibodies directed against glial fibrillary acidic protein (GFAP), keratin, S-100 protein, vimentin, and desmin. GFAP was expressed by 33% of the benign schwannomas, 40% of the neurofibromas, and 7% of the malignant schwannomas. Keratin was expressed by 7% of the benign schwannomas and 4% of the malignant schwannomas. S-100 protein was expressed by 100% of the benign NSTs and by 40% of the malignant schwannomas. Vimentin was observed in 100% of the benign NSTs and in 85% of the malignant schwannomas. None of the cases stained for desmin. GFAP and cytokeratin expression could not be predicted on the basis of tumor light microscopy or ultrastructure. These findings are of practical importance in routine surgical pathology, particularly with respect to the differential diagnosis of gliomas located in the central nervous system and in immunohistochemical studies of peripherally located, poorly differentiated neoplasms.

Topics: Desmin; Glial Fibrillary Acidic Protein; Humans; Immunohistochemistry; Keratins; Microscopy, Electron; Neurilemmoma; Neurofibroma; S100 Proteins; Vimentin

Topics: Adult; Biopsy; Diagnosis, Differential; Female; Fibroma; Follow-Up Studies; Hair; Hamartoma; Humans; Keratins; Male; Melanins; Middle Aged; Mucins; Neurofibroma; Sensory Receptor Cells; Skin; Skin Neoplasms