Folliculocystic and Collagen Hamartoma: A New Entity?

Abstract

Folliculocystic and collagen hamartoma is a newly described complex hamartoma characterized by abundant collagen deposition, concentric perifollicular fibrosis, and keratin- filled infundibular cysts that are visible on histopathological examination. Here, we report the case of a 19-year-old Korean man who had large brownish infiltrated plaques with numerous follicular comedo-like openings and subcutaneous cystic masses on his right temporal scalp and ear since birth. Histopathological examination showed abundant collagen deposition in the dermis that extended up to the subcutaneous fat layer, multifocal infundibular cysts packed with keratin, and perifollicular inflammation and fibrosis. Hence, we describe a new type of hamartoma with folliculocystic and collagen components but without tuberous sclerosis.

Tuberous sclerosis and cutaneous stigmata: ever-expanding spectrum

“…The child manifested several segmental variegate osseocutaneous stigmata in TS. Although collagenous hamartomas are linked to TS, FCCH is a recent addition to the phenotypic spectrum 1–3. It may be considered a variant of angiofibroma.…”

Folliculocystic and collagen hamartoma of tuberous sclerosis: A new case in a female patient and review of literature

“…Histopathological features of FCCH are identical in all described cases and include 3 components of the hamartoma: abundant collagen bundles infiltrating into subcutaneous tissue; concentric fibrosis around hair follicles, eccrine glands and vessels; and dilated comedo‐like openings and cysts . Some cysts may rupture and develop granulomatous inflammation.…”

“…Torrelo et al in 2011 were the first to initially describe a group of 6 patients with a distinct type of collagen hamartoma with unique histopathological features (dermal collagen deposition extending into the subdermal fat, concentric perifollicular fibrosis, comedones and infundibular keratin‐containing cysts) . As the initial description there has only been 1 additional case report of FCCH in a Korean male and a short report in a Caucasian female . In this article, we present an additional case of FCCH and discuss its histopathological features and differential diagnosis.…”

“…Known cases of FCCH are summarized in Table . Only 1 patient from the case series described by Torrelo et al as well as the case published by An et al had no systemic comorbidities (Table ) . FCCH usually presents at birth or is noted in early infancy and presents as an exophytic mass with comedo‐like openings in the surface.…”

A Rare Soft-Tissue Tumor in a 15-Year-Old Boy With Tuberous Sclerosis Complex: Answer

“…After this initial description, only 4 additional case reports have been published, including 3 female patients 1,4,5 and 1 patient without TSC. 6 FCCH histopathologically resembles angiofibroma, shagreen patches, and TSC-unrelated collagen nevi. These lesions have in common that they show coarse, rather than delicate, collagen fibers, which are often haphazardly arranged through the dermis.…”