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 Table of Contents  
Year : 2020  |  Volume : 53  |  Issue : 4  |  Page : 145-147

A rare case of proliferating trichilemmal tumour of mons pubis in an elderly male

Institute of General Surgery, Madras Medical College and Rajiv Gandhi Government General Hospital, Chennai, Tamil Nadu, India

Date of Submission24-Dec-2019
Date of Decision30-Jan-2020
Date of Acceptance26-Mar-2020
Date of Web Publication20-Aug-2020

Correspondence Address:
Mohamed Javid
Institute of General Surgery, Madras Medical College and Rajiv Gandhi Government General Hospital, E.V.R Periyar Salai, Park Town, Chennai - 600 003, Tamil Nadu
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/fjs.fjs_112_19

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Proliferating trichilemmal tumour (PTT) is a rare skin lesion arising from the isthmus region of the hair follicle, with a potential for a malignant transformation. It has a predilection for the scalp (90%) and commonly occurs in elderly females after the age of 50. However, there are various case reports suggesting that PTT can rarely arise from other areas. Here we present the case of an elderly male who came to us with an ulceroproliferative lesion in the mons pubis. A wedge biopsy suggested that the lesion was a PTT. Histopathological examination following a wide local excision confirmed the diagnosis of PTT without any foci of malignant changes. We feel this case is of interest and deserving to be reported on account of the unusual location and differential diagnosis from other diseases.

Keywords: Mons pubis, proliferating trichilemmal tumour, ulceroproliferative lesion

How to cite this article:
Javid M, Swaminathan SP, Mani R, Jebasingh AV. A rare case of proliferating trichilemmal tumour of mons pubis in an elderly male. Formos J Surg 2020;53:145-7

How to cite this URL:
Javid M, Swaminathan SP, Mani R, Jebasingh AV. A rare case of proliferating trichilemmal tumour of mons pubis in an elderly male. Formos J Surg [serial online] 2020 [cited 2022 Jun 29];53:145-7. Available from: https://www.e-fjs.org/text.asp?2020/53/4/145/292724

  Introduction Top

Proliferating trichilemmal tumour (PTT) was first described by Wilson-Jones in 1966,[1] as a rare tumor arising from the outer root sheath in the isthmus region of the hair follicle. Since then only over 100 cases have been reported in literature.[2] Also, no reports regarding the distribution of this tumour in Asia was found, highlighting the importance of reporting such cases managed in this region. This also suggests that knowledge about this condition would help Asian doctors arrive at an early diagnosis. It is commonly seen in females from fourth to eight decade.[3],[4] It commonly arises from the scalp (90%) but can also rarely arise from other locations.[5] They are usually benign tumors, but they also carry a potential for malignant transformation or even a more aggressive behaviour.[6] Treatment generally is a surgical excision of the lesion with an adequate margin. However local recurrences were reported in 3.7% of PTT.[6] Hence patients should be kept on regular follow up.

  Case Report Top

A 60-year-old male presented to us with complaints of a growing ulcerative lesion over the mons pubis for 1 month. There was no history of bleeding or any purulent discharge from the lesion or the presence of any similar lesion elsewhere. Clinical examination revealed an ulceroproliferative lesion of size 4 cm × 3.5 cm × 0.75 cm with everted edges, irregular margins in the mons pubis just above the root of the penis with absence of any similar lesion elsewhere [Figure 1]. The skin lesion was not fixed to any of the underlying structures and there was no regional lymphadenopathy.
Figure 1: A 4 cm × 3.5 cm × 0.75 cm ulceroproliferative growth with everted edges and irregular margins in the mons pubis

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Computed tomography scan on the abdomen and pelvis revealed 4.2 cm × 3.6 cm × 0.8 cm growth in skin of the anterior abdominal wall over the pubic region, with neither involvement of any underlying structures nor the presence of any significant lymphadenopathy. Edge biopsy showed features suggestive of PTT.

Subsequently a wide local excision of the lesion with 1 cm margin was done. The specimen was sent for a frozen section and it revealed tumour free margins. Hence primary suturing the wound was done. Subsequent histopathological examination of the specimen revealed stratified squamous epithelium with a neoplasm arranged in lobules and dilated cystic spaces of varying sizes. These lobules were composed of squamous epithelial cells with moderate eosinophilic cytoplasm and round to oval vesicular nuclei [Figure 2]. Focal lobules showed peripheral nuclear palisading and the centre of the lobules showed abrupt keratinisation into amorphous eosinophilic keratin material. All these features suggested the lesion to be a PTT [Figure 3].
Figure 2: Histopathology showing eosin and hematoxylin stained tumor focus in the lower part of a relatively normal skin with granular layer. (H and E, ×100)

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Figure 3: Histopathology showing the tumor foci which shows abrupt keratinization, the key feature in proliferating trichilemmal tumour, with irregular lobules. The tumor cells show moderate eosinophilic cytoplasm and round to oval vesicular nuclei. (H and E, ×400)

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The postoperative period was uneventful and the patient recovered well. The patient remained asymptomatic and no recurrence was noted during follow up at 3 months and 6 months after the surgery.

  Discussion Top

The various differential diagnosis which can be considered clinically for PTT include epidermoid cyst, keratoacanthoma, squamous cell carcinoma, pilomatrixoma, sweat gland tumors, dermatofibrosarcoma protuberans, cylindroma, basal cell carcinoma, and angiosarcoma.[6] Women are more likely to be afflicted than men and these lesions most often occur from fourth to eight decade, however there are reports of presentation in younger age groups, even as young as 18 years. Patients most often present with solitary lesions, but multiple lesions are also known to occur.[5] These tumors commonly arise from the scalp. However other sites of origin, although very rare, have been reported in the literature: these include the neck, trunk, groin, abdomen, vulva, gluteal region, upper and lower extremities, including the elbow, the dorsum of the hand, and the index finger; the face, including the forehead, nose, eyelid, lip, and intraoral; and even the base of the skull.[6] These tumors most likely do not arise from the Lanugo hair follicles of the bald scalp and follicles of other areas devoid of nonterminal hair.[7] These tumors usually arise from sun exposed areas in the body but can rarely arise from non-sun exposed areas, as in our patient.

The presentation is of an asymptomatic nodule often present for long duration, without being noticed, before a rapid increase in the size of the lesion, resulting in a lobulated and exophytic fungating mass that might ulcerate, bleed or associated with a yellowish discharge.[5] They usually have well-circumscribed borders without infiltration of adjacent tissue.[5] Features suggestive of malignancy include, nonscalp locations, size >5 cm, and recent rapid increase in size.[8] Although in our patient the lesion was present in a nonscalp location, the histopathological diagnosis suggested a benign tumor.

A proliferating trichilemmal tumor is a rare tumor originating from the outer root sheath in the isthmus region of the hair follicle.[1] Other synonyms commonly employed include subepidermal acanthoma, proliferating epidermoid cyst, proliferating trichilemmal cyst, invasive hair matrix tumor, invasive pilomatrixoma, trichochlamydocarcinoma, hydatidiform keratinous cyst, giant hair matrix tumour and trichochlamydoacanthoma.[6] PTT is usually considered to be a sequela of trauma, irritation, or inflammation and in some cases inherited in an autosomal-dominant mode, linked to chromosome 3.[9],[10] Most tumors arise within a preexisting pilar cyst.

PTT is usually benign and as suggested by Saida et al. may undergo malignant transformation with progression from an adenomatous stage of the trichilemmal cyst to an epitheliomatous stage of the PTT eventually transforming into the carcinomatous stage of the malignant PTT (MPTT).[7],[11] The histology of PTT exhibits broad bands of proliferating epithelial cells that either surround the cystic areas or are interconnected and separated by a generally fibrous, but occasionally sclerosed or cellular stroma. Within the bands, smaller basaloid cells are seen palisading at the periphery; these cells enlarge and become more squamoid as they progress toward the center.[6] The periphery of the epithelial bands often shows a thick, hyaline and eosinophilic periodic acid–Schiff positive basement membrane that might be disrupted focally.[6],[10] It is also characterized by trichilemmal keratinization, which means an abrupt transition from nucleated epithelial cells to anucleated keratinized cells, without the formation of a granular layer.[2] The essential histological features of malignancy include the presence of a high mitotic rate, atypical mitosis, severe nuclear pleomorphism, and tumor invasion of the adjacent tissues.[12] It is also suggested that CD34 and calretinin are two important immunohistochemical markers of outer root sheath differentiation, and therefore show positivity in PTT.[13]

The treatment generally accepted is a wide local excision with a 1-cm margin of normal tissue to prevent recurrence.[6] As it can help to assure precise control margin, Mohs micrographic surgery may be used to decrease the incidence of recurrence and metastasis with a minimal extent of resection.[6] If the histologic diagnosis of MPTT is made, more aggressive therapeutic measures such as nodal dissection, radiotherapy, or chemotherapy must be considered in addition to wide local excision.[6],[10] There are reports that this tumour can recur after resection and hence patients must be kept under regular follow up.[12]

Declaration of patient consent

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

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Conflicts of interest

There are no conflicts of interest.

  References Top

Wilson-Jones E. Proliferating epidermoid cysts. Arch Dermato1966;94:11-19.  Back to cited text no. 1
D'Avila D, Kanno D, de Castilho da Silva D, Pastro V, Novelli P, de Paula Freitas B, et al. A proliferating trichilemmal cyst in the perianal region: A case report. Int J Surg Case Rep 2018;53:175-8.  Back to cited text no. 2
Quiñones-Martínez A, Nieves-Ríos C, Bolaños-Ávila G. Malignant proliferating trichilemmal tumor of the forearm: A case report of an unusual location of a rare cutaneous adnexal tumor. J Surg Case Rep 2018;2018:rjy290.  Back to cited text no. 3
Yamaguchi J, Irimajiri T, Ohara K. Proliferating trichilemmal cyst arising in the arm of a young woman. Dermatology 1994;189:90-2.  Back to cited text no. 4
Al Hawsawi K, Alghamdi A, Almasry N, Aldosari M. Proliferating trichilemmal tumor (PPT): A case report and review of literature. J Health Sci 2015;5:17-9.  Back to cited text no. 5
Satyaprakash AK, Sheehan DJ, Sangüeza OP. Proliferating trichilemmal tumors: A review of the literature. Dermatol Surg 2007;33:1102-8.  Back to cited text no. 6
Saida T, Oohara K, Hori Y, Tsuhiya S. Development of a malignant proliferating trichilemmal cyst in a patient with multiple trichilemmal cysts. Dermatologica 1983;166:203-8.  Back to cited text no. 7
Vinod V, Shivani A. Proliferating trichilemmal tumour: An interesting tumour case Report. Indian J Basic App Med Res 2013;I6:591-3.  Back to cited text no. 8
Ye J, Nappi O, Swanson PE, Patterson JW, Wick MR, et al. Proliferating pilar tumors. A clinicopathologic study of 76 cases with a proposal for definition of benign and malignant variants. Am J Clin Pathol 2004;122:566-74.  Back to cited text no. 9
Wang X, Yang J, Yang W. Multiple proliferating trichilemmal tumors in a middle-aged yellow man. Tumori 2010;96:349-51.  Back to cited text no. 10
Morgado B, Agostini P, Rivero A, Silva N. Extensive and ulcerated malignant proliferating trichilemmal (pilar) tumour, arising from multiple, large, degenerated trichilemmal (pilar) cysts. BMJ Case Rep 2016;2016. pii: bcr2015209785.  Back to cited text no. 11
Sethi S, Singh UR. Proliferating trichilemmal cyst: Report of two cases, one benign and the other malignant. J Dermatol 2002;29:214-20.  Back to cited text no. 12
Agarwal C, Pujani M, Raychaudhuri S, Arora S, Rana D, Chauhan V. Squamous cell carcinoma versus malignant proliferating trichilemmal tumor: A histopathological dilemma with review of literature. Indian J Dermatol 2019;64:339.  Back to cited text no. 13
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