Folliculocystic and Collagen Hamartoma: A Distinct Hamartoma Associated With Tuberous Sclerosis Complex

Abstract

Tuberous sclerosis complex (TSC) is a neurocutaneous disease characterized by cutaneous and extracutaneous hamartomas. Dermatologic evaluation is critical for early diagnosis because mucocutaneous manifestations account for 4 of 11 major and 3 of 6 minor diagnostic criteria. Folliculocystic and collagen hamartoma (FCCH) is a recently described entity associated with TSC. We herein describe the case of a 28-year-old woman with a history of TSC who presented with a scalp lesion present since childhood. Physical examination revealed a solitary, well-circumscribed exophytic tumor over the occipital scalp measuring 9 • 8 cm and covered with comedones and cyst-like structures. Biopsy of the lesion demonstrated thickening of the collagen bundles throughout the dermis, concentric perifollicular and perivascular fibrosis, an increased number of dilated vessels, and keratin-filled cysts lined by the infundibular epithelium. Clinicopathologic correlation was diagnostic for FCCH. The patient was referred for surgical excision. In addition, we review 11 other cases of FCCH previously reported in the literature.

Histological Patterns of Skin Lesions in Tuberous Sclerosis Complex: A Panorama

“…Therefore, we believe that (like Cardona et al [ 21 ] and Treichel et al [ 15 ]), TSC-hamartomas such as FCP, AF, SP, and FCCH belong to a same histopathologic spectrum with the predominance of one or another component ( Table 2 ).…”

“…FCCH is a new entity described in 2012 by Torrelo et al with six cases in male patients with TSC [ 17 ]. Six additional cases of FCCH were reported [ 18 , 19 , 20 , 21 , 22 , 23 ], all occurring in patients with TSC, suggesting a causal relationship.…”

“…A distinctive feature of FCCH is the presence of comedo-like formation and cysts lined by an infundibular epithelium, containing intact keratin ( Figure 6 c,d). Occasionally a ruptured cyst with foreign body reaction has been seen [ 17 , 21 ]. A vascular component has also been noticed in two cases with increased and dilated blood vessels [ 19 , 23 ].…”

Miliary fibromas in tuberous sclerosis complex

“…MiF are not part of the clinical diagnostic criteria, but their presence supports a diagnosis of TSC. MiF are one member of a group of cutaneous findings that can be associated with TSC, including folliculocystic and collagen hamartomas, 6 red comets on the nails, 7 small collagenomas on the back, 8 angiofibromas on the nipples 9 or genitals, 10 and molluscum fibrosum pendulum on the neck in children 11 . MiF are typically of little concern but those affected can be reassured that they are benign and part of the spectrum of skin findings observed in TSC.…”

Folliculocystic and Collagen Hamartoma: A Subset of Fibrous Cephalic Plaque

“…On physical examination, the lesions appear as “large, painless, infiltrated plaques studded with follicular comedo-like openings and cysts containing and draining a keratinous or purulent material” [ 3 ] and have been reported on the face, scalp, abdomen, back, and thigh [ 4 ]. Since its initial characterization, 12 cases of FCCH have been reported, six of which were from the original report from Torrelo et al in 2012 [ 3 - 9 ]. Here, we present a case of FCP with infundibular cysts on the scalp and forehead in a young man with a previously established diagnosis of TSC.…”