FSCH is a distinct cutaneous hamartoma formed from epithelial and stromal elements. Among the cases of FSCH in the literature1-20
, only a few cases of giant FSCH have been reported ()3-6
. The clinical features of our case were similar to those of the reported giant FSCH cases, except for cerebriform surface and chin involvement. FSCH is slightly more common in females. The sites of predilection are the nose, cheeks, forehead, and scalp. In most cases, the lesion does not exceed 3 cm in diameter7
. The four cases in the literature described as "giant" ranged from 5 cm to 23 cm in diameter. The lesions in giant FSCH cases occurred in various sites, such as genital areas, upper extremities, and upper back.
The clinical features of the reported cases of giant folliculosebaceous cystic hamartoma
FSCH has distinct, unique, classical histopathologic features. Kimura et al1
established the histological criteria for diagnosis of FSCH as: 1. an infundibular cystic structure attached to sebaceous lobules via sebaceous ducts; 2. laminated fibroplasias around the entire fibroepithelial units; 3. mesenchymal changes around fibroepithelial units; 4. clefts between fibroepithelial units and surrounding altered stroma; 5. confinement of the process primarily to the dermis. Several variations in FSCH reflect the predominance of either epithelial or non-epithelial components. Fogt and Tahan8
reported large expanses of tufted aggregates, separated or enveloped within the epithelial units. Donati and Balus9
presented a case with neural proliferation, while Aloi et al10
described copious mucin deposits in a fibrillary stroma. Our case involved several mesenchymal changes, such as laminated collagen, vascular proliferation, and slightly increased muscle components.
Because of its peculiar histopathologic features, diagnosis of FSCH is not difficult. But, in some cases, FSCH must be differentiated from sebaceous trichofolliculoma. Sebaceous trichofolliculoma is associated with pilosebaceous hyperplasia and overgrowth5
. It presents as a central cystic cavity, usually containing a hair shaft, with sebaceous lobules and secondary hair follicles. However, sebaceous trichofolliculoma has minimal surrounding stromal proliferation. In FSCH, there are no secondary hair follicles and hair shaft in the cystic cavity. Mesenchymal change in FSCH is another point of differential diagnosis.
Giant FSCH is less common than ordinary FSCH and this particular case occurred on the face unlike other giant FSCH cases. We need to gather more cases to determine how FSCH and giant FSCH differ from each other in clinical features and prognosis.