Basaloid follicular hamartoma: A case report and review of the literature

Abstract

Basaloid follicular hamartoma (BFH) is a rare, benign, skin adnexal tumor. Several clinical patterns have been reported, but they all share the same histopathological features. BFH may be hereditary or nonhereditary and can be accompanied by systemic diseases. Microscopic examination of BFH shows branching cords and anastomosing strands of basaloid cells in a loose, fibrous stroma. The most important pathological differential diagnosis is infundibulocystic basal cell carcinoma. These two lesions must be differentiated carefully based on clinical presentation and histopathological picture, and even molecular studies may be needed. We present a report of a 78-year-old woman with a solitary, asymptomatic, slow-growing skin tumor on her left scalp. No associated systemic disorders were found. On the basis of an excisional biopsy performed on the tumor, a pathological diagnosis of sporadic BFH was made.

Basaloid tumors arising from seborrheic keratosis: Malignant basal cell carcinoma or benign basaloid follicular hamartomatous proliferation?

“…Parts of these basaloid tumor islands attached to SK were morphologically similar to BFH. BFH was first reported in 1969 as “generalized hair follicle hamartoma” and was termed by Mehregan and Baker in 1985 . Histologically, BFH consists of strands and cords of basaloid cells or cribriform basaloid islands originating from the hair follicles and embedded in a loose fibrous stroma .…”

Linear Unilateral Basaloid Follicular Hamartoma Following Blaschko's Lines: Two Case Reports and Review of the Literature

“…Solitary BFH was first described in 1992 as a smooth plaque or a papule appearing most commonly on the face or scalp . Several forms of generalized BFH have been described : sporadic form—multiple BFHs without systemic disease; generalized acquired form—female patients with generalized BFHs associated with alopecia and autoimmune diseases, such as myasthenia gravis and systemic lupus erythematosus, in which the lesions are found mainly on the face and periorificial areas; generalized familial form—an autosomal dominant disease that may or may not be associated with hypotrichosis, hypohidrosis, and palmoplantar pitting and appears on the face and genital region; and generalized congenital form—generalized BFH associated with other ectodermal defects, such as hypotrichosis and punctate keratotic pits, on the palms and soles and with cystic fibrosis.…”

“…Basaloid follicular hamartoma (BFH) is a rare follicular malformation with distinctive histopathologic patterns. A characteristic finding is the presence of branching cords and thin strands of undifferentiated anastomosing basaloid proliferations that arise from hair follicles and are embedded in a fibrous stroma , although basaloid follicular hamartomatous changes can be seen in a wide range of clinical situations: a congenital or acquired generalized type associated with systemic diseases, a localized linear and unilateral type, and a solitary plaque or nodular type . Carney reported the first case of linear and unilateral BFH in 1952, calling it linear unilateral basal‐cell nevus with comedones.…”

Letter to the Editor Basaloid follicular hamartoma on the upper eyelid

“…Basaloid follicular hamartoma is a folliculocentric tumor limited to the superficial dermis. Involvement of the deep reticular dermis or soft tissue is not seen in BFH [ 1 ].…”