FOLLICULOSEBACEOUS CYSTIC HAMARTOMA - A CLINICAL-PATHOLOGICAL STUDY

Background: Folliculosebaceous cystic hamartoma (FCH) is a recently re cognized cutaneous hamartoma comprising follicular, sebaceous, and mes enchymal elements. Only nine cases have been previously reported. Obje ctive: The aim of this study was to characterize further the clinical, histologic, and immunohistologic features of FCH. Methods: The clinic al, histologic, and immunohistologic features of eight cases of FCH we re evaluated and the literature reviewed. Results: All lesions present ed as exophytic papules or nodules on the head, most commonly the cent ral part of the face. Age at onset ranged from 4 to 47 years. The size ranged from 0.5 x 0.4 cm to 1.4 x 1.1 cm. Clinical diagnoses were nev us, neurofibroma, and adnexal tumor. None of the patients had associat ed Muir-Torre syndrome. The diagnostic microscopic features of infundi bular cystic structures with attached sebaceous glands and characteris tic stroma were present in all lesions. Many of the stromal spindle ce lls were CD34 positive. Conclusion: FCH is a recently recognized hamar toma of follicular, sebaceous, and mesenchymal elements. Although repo rted only rarely, its incidence is likely much higher.