International Journal of Trichology

: 2022  |  Volume : 14  |  Issue : 6  |  Page : 221--223

Giant solitary trichoepithelioma: A diagnosis of exclusion

Nitin Krishna Patil1, Aditya Kumar Bubna1, Seeba Hussain1, Neha Singh2,  
1 Department of Dermatology, Katihar Medical College, Katihar, Bihar, India
2 Department of Pathology, Katihar Medical College, Katihar, Bihar, India

Correspondence Address:
Aditya Kumar Bubna
Department of Dermatology, Katihar Medical College, Karim Bagh, Katihar - 854 106, Bihar

How to cite this article:
Patil NK, Bubna AK, Hussain S, Singh N. Giant solitary trichoepithelioma: A diagnosis of exclusion.Int J Trichol 2022;14:221-223

How to cite this URL:
Patil NK, Bubna AK, Hussain S, Singh N. Giant solitary trichoepithelioma: A diagnosis of exclusion. Int J Trichol [serial online] 2022 [cited 2023 May 31 ];14:221-223
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Trichoepitheliomas (TEs) are regarded as poorly differentiated hamartomas of hair germ.[1] There are three variants of TE, namely solitary, multiple, and desmoplastic. When a solitary TE is 2 cm or more in size, then it is labeled as giant solitary trichoepithelioma (GST).[2]

GST is quite an uncommon appendageal tumor to permit a ready familiarity. We hereby report a case of GST, whose diagnosis was arrived primarily by the histopathological study as a diagnosis of exclusion, because both clinical and dermoscopic findings were not very conclusive for a single entity.

A 65-year-old female presented to the dermatology outpatient department with complaints of a slowly expanding asymptomatic lesion over the forehead for the past 10 months. It began as a minuscule pea-sized papule that slowly advanced to attain the current status [Figure 1]a. On examination, an indurated, annular plaque with asymmetric thickened borders was visualized. The border was broadened over the right margin with the thickening going on to enclose almost 80% of the plaque leaving behind a central depression of size 0.3 cm × 0.3 cm. Toward the upper and outer right border of the plaque, overlying crusting/scaling was seen. The left border was considerably thinner when compared to the right side [Figure 1]b. Palpation demonstrated a firm and nontender consistency. Clinical differentials of desmoplastic TE and sclerotic basal cell carcinoma (BCC) were considered. Dermoscopy revealed short, thick white crossing lines (consistent with chrysalis pattern), few telangiectatic vessels, circular white to cream-colored structures [Figure 2]a and yellowish-brown crusts and white scales along with arborizing vessels [Figure 2]b.{Figure 1}{Figure 2}

Skin biopsy demonstrated an atrophic epidermis. Dermis was composed of islands of uniform basilar cells with peripheral palisading in few areas, and numerous keratinous cysts lined by stratified squamous epithelium. The basophilic cell nests lacked retraction clefts. Many of these nests demonstrated abortive hair follicle differentiation. The stroma exhibited a fibromyxoid consistency [Figure 3] and [Figure 4]. As facilities for cytokeratin markers were not available in our institute, this test could not be performed. Nevertheless, on careful evaluation of clinical, dermoscopic, and histopathological findings, a diagnosis of GST was finally arrived at.{Figure 3}{Figure 4}

Although the clinical morphology in our case was highly consistent with desmoplastic TE (illustrating the characteristic annular, indurated, and centrally depressed plaque); histopathology failed to demonstrate two components of the classical histopathological triad diagnostic for desmoplastic TE (viz. narrow strands of basaloid tumor cells and a desmoplastic stroma) as stated by Brownstein and Shapiro.[3] Only one component of the triad, i.e., keratinous cysts was identified, thereby excluding its diagnosis.

Histopathology, in our case, elaborated a high degree of differentiation toward follicular structures along with numerous horn cysts and abortive dermal papillae. Also, the absence of mitotic figures and a noninfiltrative pattern on microscopy further pointed toward a diagnosis of solitary TE.[4] The only finding causing doubt was the unusual clinical manifestation of the adnexal tumor. This sclerotic presentation of GST, we believe has not been previously reported and we therefore would like to highlight this new morphological pattern that we observed. Other rare phenotypes of GST that have been described in the past include subcutaneous nodules,[5] pedunculated plaques,[6] ulcerated forms,[7] and cystic lesions.[8],[9],[10],[11]

Besides, we discovered that dermoscopy was not a very specific diagnostic tool here. Nevertheless, it enabled studying the underlying dermal pathology better. A number of findings overlapping with BCC/other skin adnexal tumors were identified in our dermoscopic evaluation and have been elaborated in [Table 1], which we consider to be of diagnostic value while evaluating adnexal tumors. However, histopathology still remains the gold standard for diagnosing these appendageal tumors, the strength of which can be enhanced by immunohistochemistry.{Table 1}

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.


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