Folliculosebaceous cystic hamartoma: A clinical pathologic study

Abstract

Background: Folliculosebaceous cystic hamartoma (FCH) is a recently recognized cutaneous hamartoma comprising follicular, sebaceous, and mesenchymal elements. Only nine cases have been previously reported. Objective: The aim of this study was to characterize further the clinical, histologic, and immunohistologic features of FCH. Methods: The clinical, histologic, and immunohistologic features of eight cases of FCH were evaluated and the literature reviewed. Results: All lesions presented as exophytic papules or nodules on the head, most commonly the central part of the face. Age at onset ranged from 4 to 47 years. The size ranged from 0.5 × 0.4 cm to 1.4 × 1.1 cm. Clinical diagnoses were nevus, neurofibroma, and adnexal tumor. None of the patients had associated Muir-Torre syndrome. The diagnostic microscopic features of infundibular cystic structures with attached sebaceous glands and characteristic stroma were present in all lesions. Many of the stromal spindle cells were CD34 positive. Conclusion: FCH is a recently recognized hamartoma of follicular, sebaceous, and mesenchymal elements. Although reported only rarely, its incidence is likely much higher.