A Case of Late Stage Sebaceous Trichofolliculoma Showing Overlapping Features with Folliculosebaceous Cystic Hamartoma

Abstract

Here, we report a rare case exhibiting the common histopathologic findings of ST and FSCH, and we discuss the association between these two diseases.A 56-year-old male presented with an asymptomatic papule on the left postauricular area for several years. Physical examination revealed a single, skin-colored, firm, hairless papule that was 4×5 mm in diameter (Fig. 1). The tumor was completely removed by excision. Histopathology revealed a markedly dilated follicular cystic structure lined by a stratified squamous epithelium that was connected to the epidermis. Abundant mature sebaceous lobules radiated outward from the cystic structure, with secondary follicles in the dermis. The epithelial component was surrounded by dense, laminated, collagenous fibroplasia and the fibroepithelial unit was separated by a cleft-like space.There are mature adipocytes and perivascular mucin deposition in variable collagenous mesenchymal stroma (Fig. 2). The features of ST are similar to those of FSCH. On histopathology, FSCH involves the upper segment, particularly around the isthmus, and is characterized by an infundibular cyst, hyperplasia of the sebaceous lobules, an abundant fibrous stroma, and mesenchymal components such as collagen, adipose, vascular tissue. FSCH tumors are separated by a cleft. Although, initially thought to be

Genital Folliculosebaceous Cystic Hamartoma: A Case Report and Concise Review of the Literature

“…Due to the overlapping features reported in some lesions, it is hypothesized that FSCH may represent a late stage in development of STF. Both share similar pathogenesis background in the form of CK15-positive hair follicle stem cells activation [ 13 , 14 ].…”

Regression of Folliculosebaceous Cystic Hamartoma in the Palpebral Conjunctiva After Incisional Biopsy

“…Differential diagnosis of midline deep sublingual lesions includes dermoid/epidermoid cyst, thyroglossal duct cyst, and mucocele arising from the ectopic salivary gland. 6 Because the common differential diagnosis of the midline deep sublingual lesions does not include schwannoma for the rarity, surgeons should consider schwannoma in the differential diagnosis. Key Words: Folliculosebaceous cystic hamartoma, incisional biopsy, palpebral conjunctiva, regression F olliculosebaceous cystic hamartoma (FSCH) is a rare, benign, cutaneous hamartoma composed of follicular and sebaceous units.…”

Peculiar non‐syndromic midline variant of nevus sebaceus on the chest of an elderly male

“…While the folliculosebaceous proliferations bear some resemblance to FSCH, 2,3 contrasting features of our case are: lamellar fibroplasia and associated mesenchymal component was missing, apocrine sweat gland abnormalities were present, and sebaceous glands connected directly to the epidermis focally. Sebaceous trichofolliculoma, as described by Plewig, 4 is sometimes separated from FSCH based on the lack of a mesenchymal component 5,6 . Still, sweat gland abnormalities are not a known feature of this latter entity.…”