Follicular Basaloid Hamartoma and Associated Cutaneous Tumors: Clinical, Histopathological and Dermoscopic Aspects.

Background: Basaloid follicular hamartoma is an uncommun benign neoplasm of the hair follicule. The linear form of basaloid follicular hamartoma can be associated with basal cell carcinoma.OBJECTIVE: We report a case of a patient with multiple basal cell carcinomas developing on a congenital lesion allowing the diagnosis of basaloid follicular hamartoma on histopathology. Methods: Each lesion was evaluated by two dermatologists. All biopsy specimens were routinely stained with hematoxylin-eosin. Results: A 76 year-old-man consulted our dermatology departement for erythematous papules spread over the left lower limb. The lesion had been evolving since birth with flesh-colored to pinkish papules following Blaschko's lines from the root of the thigh to the foot. Three months before consultation, the papules increased in size leading to nodules with sometimes an ulcerated center. Dermoscopy under polarized mode displayed for ulcerated lesions (A) yellow-brownish crusts and ulceration surrounded by blue-grey ovoid nests, subtle short white streaks, brown dots and linear/arborising vessels. For nodular lesions (B), dermoscopic features are white pinkish hue, dotted and linear vessels, brown dots, blue-grey structureless areas and white prominent shiny streaks. There were some more erythematous inflamed and eroded areas in the background with a reversed honeycomb white network on dermoscopy (C), polymorphous vessels, whitish scales, ulcerations and milia-like cysts. The background lesion showed varied dermoscopic structures on a flesh colored slightly pinkish bottom (D). Histolopathology concluded for lesions A to an infiltrating and nodular basal cell carcinoma, (B) and (C) to fibroepithelioma of Pinkus and (D) to basaloid follicular hamartoma. Conclusion: Several case reports have documented dermoscopic features of a solitary basaloid follicular hamartoma. However, further studies are required to specify any reproducible features.