|LETTER TO EDITOR
|Year : 2020 | Volume
| Issue : 1 | Page : 52-53
Cystic follicular hamartoma: A rare case report
Chirag Ashwin Desai1, Saurabh Shah2
1 Divya Sparsh Skin and Hair Clinic, Mumbai, Maharastra, India
2 Advanced Skin and Hair Clinic, Mumbai, Maharastra, India
|Date of Submission||08-Apr-2020|
|Date of Decision||18-Apr-2020|
|Date of Acceptance||25-Apr-2020|
|Date of Web Publication||02-Jun-2020|
Chirag Ashwin Desai
Divya Sparsh Skin and Hair Clinic, Mumbai, Maharastra
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Desai CA, Shah S. Cystic follicular hamartoma: A rare case report. Indian J Dermatopathol Diagn Dermatol 2020;7:52-3
A cyst is defined a space enclosed by an epithelial lining. The space may contain keratin or secretions depending on the type of cyst. Depending on the components in the lining and the cystic contents, it is classified into various types.
A 71-year-old man presented with an asymptomatic lesion on the scalp with a central pore for 5–6 years. On examination, the lesion was brownish in color with a central dark depression. The lesion was nontender and cystic in consistency on palpation. Some serous material emanated from it on pressing the lesion. Surrounding skin appeared unremarkable [Figure 1]. Preliminary differential diagnoses of epidermoid cyst, trichilemmal cyst, and trichofolliculoma were kept. Biopsy revealed a circumscribed cystic structure lined by stratified squamous epithelium with well-defined granular layer. The wall of the cyst was connected with reticular proliferations of eosinophilic (isthmic) and basophilic (follicular germinative) cells. At the periphery, the basophilic cells formed a palisade arrangement, and they were accompanied by discrete aggregations of stromal fibroblasts in a “germ and papilla” arrangement. Sebaceous glands and rudimentary hair follicles were seen attached to places. Horn cysts and pseudohorn cysts were seen within the cyst wall. The contents of the cyst were made up of lamellated orthokeratin. Surrounding dermis showed moderately dense perivascular lymphocytic infiltrate with few plasma cells and fibroplasia. The overlying epidermis was unremarkable [Figure 2], [Figure 3], [Figure 4].
|Figure 2: Cystic structure with cords forming reticulate pattern at places and comprising eosinophilic (isthmic) and basophilic (follicular germinative) cells (H and E, ×4)|
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|Figure 3: Cystic structure with attached rudimentary hair follicles and sebaceous glands (H and E, ×4)|
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|Figure 4: Cyst wall comprising follicular germinative cells and stromal fibroblasts in a germ-papilla arrangement (black arrows) (H and E, ×~10)|
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Neoplasms and hamartomas showing follicular germinative differentiation imply cells showing features similar to evolving follicular germ in an embryo. There is a lot of confusion in the literature with regard to cystic lesions which show follicular germinative differentiation in the wall. Important considerations being cystic trichoblastoma (CTB), cystic panfolliculoma, cystic basal cell carcinoma, and a newly classified entity called cystic follicular hamartoma. CTB is predominantly composed of a cystic space that contains keratin and lined by stratified squamous epithelium with granular layer resembling the infundibulum of the hair follicle, with solid aggregations and cords composed of follicular germinative cells which are surrounded by fibroblasts in the neighboring stroma in a germ and papilla arrangement. Our case showed similar features; however, there were sebaceous glands and rudimentary hair follicles also attached to the lining which distinguished it from CTB.
Possibility of cystic panfolliculoma was ruled out in our case because we were unable to find all possible structures differentiating toward the upper and lower segments of the hair follicle. Cells differentiating toward inner root sheath with eosinophilic trichohyaline granules were not seen even on deeper sections. Crowding of cells, necrotic cells, and clefting between the follicular germinative cells and surrounding stroma were absent, and mitotic figures were rare which differentiated our case from cystic basal cell carcinoma. Trichofolliculoma is characterized by mature secondary follicles attached to the central cystic primary follicle. However, in our case, only rudimentary hair follicles were seen attached.
Our case would be best called cystic follicular hamartoma, as per the classification of cystic lesions showing follicular germinative differentiation proposed by López-Takegami et al. We describe this case in order to increase the awareness of this rare entity among the dermatopathologists.
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|| |
Juárez A, Rütten A, Kutzner H, Requena L. Cystic trichoblastoma (so-called trichoblastic infundibular cyst): A report of three new cases. J Cutan Pathol 2012;39:631-6.
Alkhalidi HM, Alhumaidy AA. Cystic panfolliculoma of the scalp: Report of a very rare case and brief review. Indian J Pathol Microbiol 2013;56:437-9.
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López-Takegami JC, Wolter M, Löser C, Maiweg C, Jones M, Metze D, et al
. Classification of cysts with follicular germinative differentiation. J Cutan Pathol 2016;43:191-9.
[Figure 1], [Figure 2], [Figure 3], [Figure 4]