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CASE REPORT Table of Contents   
Year : 2008  |  Volume : 51  |  Issue : 2  |  Page : 277-279
Trichoadenoma of Nikolowski

Department of Pathology, Narayana Medical College, Nellore, AP, India

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Trichoadenoma of Nikolowski is a rare benign cutaneous tumor, which is usually solitary, nodular and occurs on the face or buttocks any time during adult life. The morphological differentiation of trichoadenoma is situated between a trichofolliculoma and a trichoepithelioma with hair follicle-like direction of differentiation. We report this case of trichoadenoma in a 28-year-old man who presented with a solitary nodular and ulcerated swelling in the gluteal region, gradually increasing in size. Excision biopsy revealed characteristic features consistent with trichoadenoma. We report this case in view of its rarity.

Keywords: Hair follicle tumors, trichoadenoma

How to cite this article:
Krishna Swaroop DS, Ramakrishna B A, Bai SJ, Shanthi V. Trichoadenoma of Nikolowski. Indian J Pathol Microbiol 2008;51:277-9

How to cite this URL:
Krishna Swaroop DS, Ramakrishna B A, Bai SJ, Shanthi V. Trichoadenoma of Nikolowski. Indian J Pathol Microbiol [serial online] 2008 [cited 2020 Jan 18];51:277-9. Available from: http://www.ijpmonline.org/text.asp?2008/51/2/277/41695

   Introduction Top

Trichoadenoma is a rare benign, well differentiated solitary and slowly growing tumor of the hair follicle, first described by Nikolowski in 1958. [1] It most commonly presents on the face and, to a lesser extent, the buttocks of adults, occurring equally in men and in women. [2] The clinical appearance is misleading, suggesting a diagnosis of basal cell carcinoma or epidermal cyst. [1]

This tumor is less mature than trichofolliculoma and is more differentiated than trichoepithelioma, with a differentiation towards the infundibular portion of the pilosebaceous canal. [3]

We report this case in a male aged 28 years with complaint of a solitary and slowly growing mass with ulceration, situated in the gluteal region. Histopathological study of the excised mass revealed characteristic features of numerous keratinous cysts without hair shaft formation throughout the dermis and surrounded by eosinophilic epithelial cell clusters.

   Case History Top

A male aged 28 years, dumb and deaf on the left side since birth, presented with a painful swelling in the upper, inner gluteal cleft region, which was gradually increasing in size since 6 months. Clinical examination revealed a solitary mass measuring 3 cm × 1 cm with ulceration on the surface without any discharge. The results of systemic and laboratory investigations were within normal limits. Serological tests for HIV, HbsAg and HCV were negative. A clinical diagnosis of fibroma was made. The mass was excised and sent for a histopathological study.

Morphological examination

Gross: Received a single, skin-covered soft-tissue mass measuring 4 cm × 2 cm × 1 cm. The skin showed ulceration on the surface, measuring 3 cm × 1 cm. Cut section was grayish-white.

Microscopic: Examination revealed tumor with ulceration of the overlying epidermis. The circumscribed tumor was composed of a number of horn cysts in the dermis [Figure 1]. These cysts contained laminated keratin and were surrounded by eosinophilic epithelial cells with attempted glandular formation and a resemblance to trichoepithelium, without hair follicle formation [Figure 2]. Solid eosinophilic epithelial cell islands without central keratinization were also noted [Figure 3]. Focal areas showed neutrophilic abscess and foreign-body reaction to ruptured cysts. No evidence of malignancy was found. Based on the above histological findings, a diagnosis of a trichoadenoma was made.

   Discussion Top

Trichoadenoma is a benign neoplasm of the hair follicle, occurring as a solitary tumor on the face (57.5%) or buttocks (24.2%), ranging from 3 mm to 50 mm in diameter; and it may arise any time during adult life in either of the sexes. [1],[2],[3],[4] Very occasionally the neck, upper arm, thigh, [2] shoulder, [3] and shaft of penis [5] may also be affected.

Rare case reports of trichoadenoma arising as combined malformations associated with intradermal melanocytic nevus; [6] and its unusual simultaneous occurrence along with sebaceous carcinoma, basal cell carcinoma, syringocystadenoma papilliferum and trichoblastoma within a nevus sebaceous have also been recorded. [7]

Microscopic study of trichoadenoma characteristically shows numerous horn cysts throughout the dermis, surrounded by eosinophilic epithelial cells. The eosinophilic cells greatly resemble the eosinophilic cells that are often seen in trichoepithelioma located between the basophilic cells and the central horn cysts. [4] The central cystic cavity shows epidermoid keratinization and resembles the cross section of infundibular portion of pilosebaceous canal without any evidence of hair follicle formation. Solid epithelial islands of eosinophilic epithelial cells without central keratinization can also be seen. [2],[4],[7]

Foci of foreign-body granuloma are present at the sites of ruptured horn cysts. [6]

Trichoadenoma is believed to be midway between trichoepithelioma and trichofolliculoma in terms of morphological differentiation - where the trichoepithelioma, an autosomal dominant disorder, typically consists of predominantly uniform basaloid cells with peripheral palisading arrangement in nests, trabeculae; or cribriform patterns, indistinguishable from those of basal cell carcinoma. Small horn cysts filled with keratin are usually present within the basaloid epithelial nests surrounded by dense fibroblastic stroma. [2],[4],[8]

At the other end of the spectrum, the trichofolliculoma is a benign hamartomatous lesion that develops at any age, typically involving the face and representing abortive differentiation of cutaneous pluripotent stem cells towards hair follicles. [8] Histologically, trichofolliculomas consist of a centrally located, unilocular or multilocular keratin-filled cystic cavity with hair shaft fragments, lined by infundibular squamous epithelium with prominent granular layer. Numerous secondary and tertiary hair follicles surrounded by variable numbers of sebaceous glands bud out and branch radially into a fibrotic stroma. [2],[4],[8]

Immunohistochemical studies have shown cytokeratin expression in trichoadenoma, suggesting differentiation towards the follicular infundibulum, [9,10] and they have shown negative findings for eccrine differentiation. [3]

In conclusion, trichoadenoma still remains as enigmatic as it was when first reported 49 years ago by Nikolowski, in terms of its morphological differentiation, which even today is "probably" towards follicular infundibular portion of the pilosebaceous canal.

   References Top

1.Reibold R, Udeutsch W, Fleiner J. Trichoadenoma of Nikolowsky-review of four decades and seven new cases [in German]. Hautarzt 1998;49:925-8.  Back to cited text no. 1    
2.Brenn T, McKee PH. Tumors of the hair follicle. In: McKee PH, Calonje E, Granter SR, editors. Pathology of the Skin with Clinical Correlations . 3 rd ed. Elsevier: Mosby; 2005. p. 1519-63.  Back to cited text no. 2    
3.Yu HJ, Yang HY, Kim YS. A case of Trichoadenoma. Korean J Dermatol 1998;36:372-5.  Back to cited text no. 3    
4.Klein W, Chan E, Seykora JT. Tumors of the epidermal appendages. In : Elder DE, Elenitsas R, Johnson BL, Murphy GF, editors. Levers histopathology of the skin. 9 th ed. Lippincott: Williams and Wilkins; 2005. p. 867-926.  Back to cited text no. 4    
5.Pavithran K, Vijayalakshmy A. Trichoadenoma of nikolowsky. Indian J Dermatol 1996;41:106-7.  Back to cited text no. 5    
6.Gonzalez-Vela MC, Val-Bernal JF, Garcia-Alberdi E. Trichoadenoma associated with an intradermal melanocytic nevus: A combined malformation. Am J Dermatopathol 2007;29:92-5.  Back to cited text no. 6    
7.Yamaguchi J, Takino C. A case of trichoadenoma arising in the buttock. J Dermatol 1992;19:503-6.  Back to cited text no. 7  [PUBMED]  
8.Alsaad KO, Obaidat NA, Ghazarian D. Skin adnexal neoplasms-part 1: An approach to tumors of the pilosebaceous unit. J Clin Pathol 2007;60:129-44.  Back to cited text no. 8  [PUBMED]  [FULLTEXT]
9.Ouchi Y, Konohana I, Okura M. A case of trichoadenoma. Jpn J Clin Dermatol 2007;61:50-2.  Back to cited text no. 9    
10.Kurokawa I, Mizutani H, Nishijima S, Kato N, Yasui K, Tsubura A. Trichoadenoma: Cytokeratin expression suggesting differentiation towards the follicular infundibulum and follicular bulge regions. Br J Dermatol 2005;153:1084-6.  Back to cited text no. 10  [PUBMED]  [FULLTEXT]

Correspondence Address:
Duddi Sreehari Krishna Swaroop
Department of Pathology, Narayana Medical College, Chinthareddypalem, Nellore - 524 002, Andhra Pradesh
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0377-4929.41695

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  [Figure 1], [Figure 2], [Figure 3]

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