Genital folliculo‐sebaceous cystic hamartoma: A claim of the stroma as a clue in the diagnosis of proliferations with follicular differentiation

Abstract

Folliculo-sebaceous hamartomas comprise a series of entities whose boundaries are imprecise. We present the clinical case of a folliculo-sebaceous cystic hamartoma of genital localization where the diagnosis was established based on the epithelial proliferation, but mostly, on the characteristic stroma. Because this lesion lacked of the cystic component, we mention the most frequent differential diagnoses and review the literature of the few cases published on this infrequent localization.

A case of folliculosebaceous cystic hamartoma: a rare and clinically indistinct lesion

“…This follicular proliferation is itself embedded in a stroma of distinct mesenchymal tissues including adipocytes, blood vessels, collagen, and mucin as was prominent in our case [5]. FSCH completely involves the dermis with a unaffected dermis [5]. Histopathological exam of our the cystic and follicular architecture associated with FSCH, yet also displayed a retiform and slightly primitive epithelial proliferation associated with the stromal component.…”

“…FSCH refers to a follicular proliferation in which sebaceous components are found within a cystic infundibular structure [5]. This follicular proliferation is itself embedded in a stroma of distinct mesenchymal tissues including adipocytes, blood vessels, collagen, and mucin as was prominent in our case [5].…”

“…In contrast to FSCH, nevus lipomatosus superficialis Dermatology Online Journal || Case Presentation does not have epithelial components and instead consists completely of adipose cells [7]. In trichofolliculoma the infundibular cyst wall is connected to multiple vellus hair follicles, whereas in sebaceous trichofolliculoma the cystic wall is linked to mature sebaceous lobules [2,4,5]. Unlike both trichofolliculoma and sebaceous trichofolliculoma, FSCH is marked by a distinct mesenchymal stroma that is delineated by a cleft from the surrounding fibroepithelial components of the dermis [2,4].…”

“…Typically the size of the lesion is less than 2cm [4]. Clinical findings alone rarely lead to the diagnosis of FSCH [5]. Indeed the vague presentation of the lesion leads to a broad differential diagnosis often including melanocytic nevi, epidermal cysts, basal cell carcinoma, soft fibromas, and sebaceous hyperplasia [2].…”

Bright lobulated tumor on the face in a newborn

“…These findings suggested the possibility that adipocytes and other mesenchymal components in FSCH originated from nestin-positive multipotent stem cells. 9,10 O RCI D Ana María Sáenz https://orcid.org/0000-0002-6660-2835…”