title: An unusual hamartoma of the folliculosebaceous-apocrine unit: a case report.
abstract: Hamartoma is a neoplasm-like lesion composed of an abnormal mixture of tissues native to the area. We report on an unusual example of a hamartomatous lesion that showed an abnormal mixture of elements of the folliculosebaceous-apocrine unit and arrector pili muscle. A 13-year-old female presented with two nodules situated 2 cm apart on the lower leg that were present since birth. The patient reported some enlargement and slight pain of the otherwise asymptomatic lesions during 2 years, before they were surgically removed. The patient obviously had no skin problems afterwards; her 12-year follow-up was significant for leucopenia and nephrolithiasis. The biopsies from both lesions looked identical. Each lesion was biphasic, i.e. composed of a predominant mesenchymal component and epithelial elements. The mesenchymal part resembled a leiomyoma, or in minor areas, the constituting cells had a myofibroblastic appearance. Encased within the mesenchymal component were large infundibulocystic structures and plentiful grouped and scattered roundish solid epithelial nodules, duct-like, glandular, and tubular elements. Some of the epithelial structures were reminiscent of those seen in tubular apocrine adenoma; others resembled syringomatous elements. We interpreted this unusual lesion as a hamartoma of the folliculosebaceous-apocrine unit.
authors.affiliation: Sikl's Department of Pathology, Charles University, Medical Faculty Hospital, Pilsen, Czech Republic. kazakov@medima.cz
authors.forename: Dmitry V
authors.initials: DV
authors.lastname: Kazakov
authors.forename: Petr
authors.initials: P
authors.lastname: Mukensnabl
authors.forename: Michal
authors.initials: M
authors.lastname: Michal
mesh_terms: D000293:Adolescent; D001050:Apocrine Glands / Q000378:metabolism / Q000473:pathology*; D005260:Female; D006201:Hair Diseases / Q000150:complications / Q000378:metabolism / Q000473:pathology; D018859:Hair Follicle / Q000378:metabolism / Q000473:pathology*; D006222:Hamartoma / Q000150:complications / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D007669:Kidney Calculi / Q000150:complications; D007970:Leukopenia / Q000150:complications; D012625:Sebaceous Gland Diseases / Q000150:complications / Q000378:metabolism / Q000473:pathology*; D012871:Skin Diseases / Q000150:complications / Q000378:metabolism / Q000473:pathology*