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Table of Contents 
Year : 2022  |  Volume : 67  |  Issue : 3  |  Page : 317
Folliculocystic and collagenous hamartoma: A rare cutaneous manifestation of tuberous sclerosis

1 Department of Dermatology, Venereology and Leprology, Christian Medical College and Hospital, Vellore, Tamil Nadu, India
2 Department of Pathology, Christian Medical College and Hospital, Vellore, Tamil Nadu, India
3 Department of Respiratory Medicine, Christian Medical College and Hospital, Vellore, Tamil Nadu, India

Date of Web Publication22-Sep-2022

Correspondence Address:
Dharshini Sathishkumar
Department of Dermatology, Venereology and Leprology, Christian Medical College and Hospital, Vellore, Tamil Nadu
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijd.ijd_88_22

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How to cite this article:
Shajil C, Sathishkumar D, Baitule A, Chandy S. Folliculocystic and collagenous hamartoma: A rare cutaneous manifestation of tuberous sclerosis. Indian J Dermatol 2022;67:317

How to cite this URL:
Shajil C, Sathishkumar D, Baitule A, Chandy S. Folliculocystic and collagenous hamartoma: A rare cutaneous manifestation of tuberous sclerosis. Indian J Dermatol [serial online] 2022 [cited 2022 Sep 30];67:317. Available from:


A 27-year-old female with tuberous sclerosis complex (TSC) was referred to Dermatology for a gradually enlarging painless mass on her scalp with intermittent pus discharge from 5 years of age. She was admitted with bilateral spontaneous pneumothorax secondary to lymphangioleiomyomatosis. Except for an episode of seizure in her childhood which was neither evaluated nor treated and nose disfigurement following native medicine application, there was no relevant past or family history. Examination revealed a 6 × 6 cm, firm, exophytic tumour with an irregular surface, over the right parietal scalp, exhibiting multiple comedo-like openings, with some discharging purulent material [Figure 1]a. She had angiofibromas, ungual fibromas, skin tags on examination [Figure 1]b,[Figure 1]c,[Figure 1]d,[Figure 1]e, lymphangioleiomyomatosis and renal angiomyolipomas on imaging, thus fulfilling the diagnostic criteria for TSC. Although the tumour clinically resembled a fibrous cephalic plaque (FCP), the histopathological features [Figure 2] were consistent with folliculocystic and collagenous hamartoma (FCCH).
Figure 1: (a) A firm plaque of size 6 × 6 cm with multiple comedo-like openings discharging purulent material (white arrow) over the right parietal scalp, (b) multiple angiofibromas over the centrofacial area, (c) ungual fibromas involving the toes, (d) and fingers (white asterisk), and (e) soft, pedunculated pigmented papules over the neck (molluscum pendulum)

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Figure 2: (a) Keratin containing cystic invagination of epithelium surrounded by abundant hyaline, eosinophilic collagen bundles in the dermis (H and E, ×40). (b) Cystic invagination of the stratified squamous epithelium, filled with laminated keratin, with focal follicular differentiation (blue box), and adjacent dermal collagenisation (H and E, ×40). (c) Rudimentary follicular structure arising from the cyst lined by stratified squamous epithelium containing granular layer (H and E, ×200). (d) Increased collagenisation of the adjacent dermis highlighted by Masson's trichrome stain (Masson's trichrome, ×40)

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TSC is a dominantly inherited neurocutaneous syndrome characterized by hamartoneoplastic proliferation in multiple organs including the skin. The FCCH is one such benign tumour with intriguing clinicopathological features, reported in 13 cases of TSC since 2012.[1],[2],[3],[4]

It presents as a painless plaque or an exophytic tumour, with an irregular surface studded with comedonal openings and variably sized cysts, occasionally draining keratinous or purulent material. It appears at birth or during infancy, commonly in males, over the scalp, abdomen, lumbar region, thighs, and face.[1],[2],[3],[4],[5] Although our patient developed FCCH at a later age and lacked cystic protuberances, the prominent comedonal openings draining keratinous material were suggestive of FCCH. Of the 14 reported cases (including ours), six are female, thus contradicting the earlier assumption of male gender predilection and questioning the role of sex hormones in its development.[1],[2],[3],[4],[5] Being a recently described rare entity, its pathogenesis is unverified. Although mutation in TSC1/TSC2 leading to uncontrolled cell proliferation, explains its hamartomatous nature, it fails to explain its occurrence in patients without TSC and its unique histology.[1],[5]

The hallmark histopathological findings of FCCH are abundant thick, hyaline, eosinophilic, collagen bundles in the dermis, concentric perifollicular fibrosis and keratin-filled infundibular cysts with dilated openings.[1],[2],[3],[4],[5] All except perifollicular fibrosis were demonstrated in our patient. Although increased dermal collagenisation is an attribute shared by FCCH, angiofibromas, FCP and shagreen patches, thus representing a histopathological spectrum, features such as infundibular cysts and perifollicular fibrosis are unique to FCCH.[1],[3]

Malignant transformation of FCCH is unknown, and although majority of the reported cases have neurological involvement, its prognostic significance needs to be ascertained.[1] Surgical excision is done when the lesion is disfiguring and recurrent keratinous discharge is distressing for the patient.[1],[5]

With increasing evidence of this rare association, the focus should be on further clarification of its epidemiology, predisposing factors, evolution, complications, prognostic significance, the effects of topical/systemic sirolimus and recurrences. More cases should be reported to facilitate this and to get the clinicians acquainted with this recent addition to the cutaneous hamartomas in TSC. With better comprehension, FCCH could prove to be a more specific feature of TSC justifying its potential inclusion in its diagnostic criteria.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.

   References Top

Cardona R, Cancel-Artau KJ, Carrasquillo OY, Martin-Garcia RF. Folliculocystic and collagen hamartoma: A distinct hamartoma associated with tuberous sclerosis complex. Am J Dermatopathol 2021;43:67-70.  Back to cited text no. 1
Roca-Ginés J, Torres-Navarro I, Llavador-Ros M, Évole-Buselli M. Folliculocystic and collagenous hamartoma of tuberous sclerosis complex, not always a single cutaneous lesion. Pediatr Dermatol 2020;37:1195-7.  Back to cited text no. 2
Madaan P, Saini L, Sankhyan N, De D, Kesavan S, Mukherjee S, et al. Tuberous sclerosis and cutaneous stigmata: Ever-expanding spectrum. Arch Dis Child 2020;105:797-7.  Back to cited text no. 3
Ehara Y, Yoshida Y, Higaki-Mori H, Yamamoto O. Treatment with sirolimus gel for folliculocystic and collagen hamartoma in tuberous sclerosis complex. Dermatol Sin 2021;39:163.  Back to cited text no. 4
  [Full text]  
Torrelo A, Hadj-Rabia S, Colmenero I, Piston R, Sybert VP, Hilari-Carbonell H, et al. Folliculocystic and collagen hamartoma of tuberous sclerosis complex. J Am Acad Dermatol 2012;66:617-21.  Back to cited text no. 5


  [Figure 1], [Figure 2]


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