IP Indian Journal of Clinical and Experimental Dermatology 2021;7(1):84–85 Content available at: https://www.ipinnovative.com/open-access-journals IP Indian Journal of Clinical and Experimental Dermatology Journal homepage: www.ijced.org/ Case Report Trichoadenoma of vulva: A rare case with rare site of presentation Haradanahalli Nagaraju Pavithra 1, *, Ranjeev Bhagat 1 , Mala Bhalla 2 1 Dept. of Pathology, Govt. Medical College and Hospital, Chandigarh, India 2 Dept. of Dermatology and Venereology, Govt. Medical College and Hospital, Chandigarh, India ARTICLE INFO Article history: Received 13-10-2020 Accepted 02-01-2021 Available online 22-02-2021 Keywords: adnexal tumor hair follicle differentiation trichoadenoma ABSTRACT Trichoadenoma is a rare benign adnexal tumor of skin with differentiation towards hair structure. It was first described by Niklowski in 1958 and so is also known as trichoadenoma of Nikolowski. It shares its features with trichoepithelioma and trichofolliculoma, which are the other common benign adnexal tumors with differentiation towards hair structure. Vulva being an unusual site for occurrence of trichoadenoma, there are very few cases reported in the literature at this site. Here we report a case of trichoadenoma of vulva. © This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. 1. Case History A 47-year-old female presented with a well-defined skin colored non-tender asymptomatic nodule of 1x1cm over the vulva for almost one year. There was no history of any sexually transmitted disease. General physical examination was within normal limits and there was no inguinal lymphadenopathy. Haemotological and biochemical investigations were within normal limits. Serological tests for syphilis and HIV were non reactive. The clinical possibilities considered were inclusion cyst and skin tag. The nodule was excised and sent for histopathology. (Figure 1) The sample was processed for routine histopathological examination. The hematoxylin and eosin stained sections were examined under light microscopy. The epidermis was relatively unremarkable. Dermis shows numerous horn cysts lined by multiple layers of eosinophilic cells. There was attempted gland formation at places. Some of the cysts were dilated. Few islands of eosinophilic cells without keratinization are seen. Occasional cysts showed presence of granular layer between the keratin and eosinophilic cells. One of the cysts ruptured eliciting lymphohistiocytic * Corresponding author. E-mail address: drpavithrahn@gmail.com (H. N. Pavithra). reaction in the surrounding area. (Figure 2) There were no basaloid cells surrounding the eosinophilic cells. There were no hair shafts. 2. Discussion Adnexal tumors of skin are an interesting and complex entity in dermatopathology. It is important to differentiate the adnexal tumors as benign and malignant and also differentiate them from the epidermal and epithelial tumors. Hair follicle and its pilosebaceous unit are adnexal structures with different group of tumors. This group comprises of various tumors with differentiation towards hair structure. Trichoadenoma is one among them which is also know as trichoadenoma of Nikolowski. 1–4 Its common presentation is on face and buttocks in adults with more than 50% cases occurring over the face. Other common sites are thigh, shoulder and neck. 3,5 Trichoadenoma commonly presents as a skin colored lesion. The histopathology will be similar to that of our case. In addition, rare islands may show granular layer with keratohyaline granules. 1–3 Absence of basaloid cells around the eosinophilic cells differentiates it from the trichoepithelioma and absence of hair shaft differentiates it from trichofolliculoma. https://doi.org/10.18231/j.ijced.2021.017 2581-4710/© 2021 Innovative Publication, All rights reserved. 84