title: Benign polymorphous mesenchymal tumor (mesenchymal hamartoma) of soft parts. Report of two cases.
abstract: We report two cases of a previously unrecognized neoplasm, each characterized by prominent lobular configuration in the subcutaneous tissue. Within the neoplasms were distinctive garland-shaped structures composed of glial fibrillary acidic protein (GFAP) positive cells with indistinct borders, encased in concentric loops of fine collage fibers. In some areas, the neoplastic cells were distributed in small lacunae. The extracellular space between the collagenous tissue and the cells was filled with copious myxoid matrix. One of the neoplasms also demonstrated areas with spindle cells which resembled leiomyoma. Immunohistochemistry was negative for smooth muscle actin (1A4), muscle actin (HHF35), S-100 protein, desmin, cytokeratin, KP1, and epithelial membrane antigen (EMA.) Currently, both patients are free of recurrence or metastasis 2 and 4 years after primary surgical excision. The neoplasms, which we term benign polymorphous mesenchymal tumor of soft parts (BPMT), should be distinguished from ossifying fibromyxoid tumor of soft parts, extraskeletal mesenchymal chondrosarcoma, neoplasms arising in ectopic breast tissue and mixed tumor of the skin.
authors.affiliation: Department of Pathology, Medical Faculty, Charles University, Pilsen, Czech Republic.
authors.forename: M
authors.initials: M
authors.lastname: Michal
authors.forename: L
authors.initials: L
authors.lastname: Sokol
mesh_terms: D000199:Actins / Q000032:analysis; D000328:Adult; D003893:Desmin / Q000032:analysis; D005260:Female; D005904:Glial Fibrillary Acidic Protein / Q000032:analysis; D006222:Hamartoma / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D007633:Keratins / Q000032:analysis; D008875:Middle Aged; D018396:Mucin-1 / Q000032:analysis; D009418:S100 Proteins / Q000032:analysis
chemical_list: D000199:Actins; D003893:Desmin; D005904:Glial Fibrillary Acidic Protein; D018396:Mucin-1; D009418:S100 Proteins; D007633:Keratins