[Folliculosebaceous cystic hamartoma: anatomo-clinical study]

Area of Science:

• Dermatopathology
• Histology
• Clinical Dermatology

Background:

• Folliculosebaceous cystic hamartoma (FSCH) is a rare cutaneous malformation characterized by follicular and sebaceous elements.
• A distinct stromal component containing adipocytes is a key feature of FSCH.

Observation:

• A retrospective study analyzed 25 FSCH cases diagnosed between 1985 and 2011.
• Lesions were typically flesh-colored, dome-shaped or pedunculated nodules, predominantly on the face (60%), with a mean duration of 9 years.
• Clinicians rarely suspected FSCH, often misdiagnosing it as other benign growths.

Findings:

• Histopathological examination consistently revealed follicular cysts, sebaceous glands, and an adipocyte-rich fibrous stroma in all cases.
• Variations included mucinous stroma, neuroid components with S100 expression, and rudimentary hair follicles.
• One case presented as a large pedunculated nodule with a proliferating cyst; only one recurrence was noted after 5 years.

Implications:

• FSCH is an underdiagnosed, benign entity, commonly presenting on the face, particularly the nose.
• Accurate histological identification relies on recognizing the characteristic adipocytes and fibrous stroma.
• Distinguishing FSCH from similar lesions like nevus lipomatosus superficialis and trichofolliculoma is crucial for correct diagnosis and management.