Clinicopathological and dermoscopic features in a case of linear and unilateral basaloid follicular hamartoma

Abstract

Linear and unilateral basaloid follicular hamartoma (BFH) is a rare disease that manifests with papules and plaques with distribution along lines of Blaschko. It runs a benign course but with the risk of basal cell carcinoma (BCC) in long term course. BCC can be differentiated from BFH with histopathology and immunohistochemistry. Dermoscopic features of BCC are well studied. Dermoscopic features of BFH are not yet described in literature in detail probably due to rarity of the disease. Here, we present a case of extensive linear and unilateral BFH with its clinicohistopathological and dermoscopic features. The lesions were extensive to involve scalp, face, neck, upper, and lower trunk. Dermoscopy revealed features similar to that of BCC including brown-grey globules and dots, in focus dots, brown linear and arciform structures, crown vessels, short fine telangiectasias, spoke wheel like structures without central dark point, white structureless areas with telangiectasias and keratotic plug. Other dermoscopic features of BCC like arborizing vessels, blue-grey ovoid nests, maple leaf-like areas, concentric structures, ulcerations, erosions and white streaks were absent in this case.

Familial multiple basaloid follicular hamartoma

“…Although FMBFH generally presents at birth or in early childhood, milder variants may be recognized later in life [6,7]. Generalized forms of BFH are usually associated with systemic manifestations, which vary according to the subtype and can include cystic fibrosis, diffuse alopecia, and various autoimmune diseases (such as myasthenia gravis or systemic lupus erythematosus), [2,8,9]. Other systemic diseases, such as hypertension, diabetes mellitus, or breast cancer, have also been reported in these patients, although it is unclear if this association exceeds that found in the general population.…”

“…Vismodegib, an inhibitor of the hedgehog signaling pathway, might play a role in the treatment of severe disease in the future [12]. The prognosis is usually excellent, unless associated systemic disorders and/or BCC develop [8,9].…”

Dermoscopic findings of de novo syringocystadenoma papilliferum

“…Another close differential diagnosis is linear unilateral basaloid follicular hamartoma, dermoscopically distinguished by brown-gray globules and dots, in focus dots, brown linear and arciform structures, crown vessels, short fine telangiectasias, spoke wheel-like structures without a central dark point, white structureless areas with telangiectasias and keratotic plug. 7 To conclude, the dermoscopic pattern consisting of a central crater surrounded by a white homogenous area , representing cystic invagination and surrounding epidermal hyperplasia respectively, can be a valuable diagnostic clue for de novo syringocystadenoma papilliferum. Additionally, we have described two novel dermoscopic features-shiny white lines and rosette.…”