Solitary Trichoepithelioma of the Eyelid: A Clinico-Pathological Correlation.

Solitary trichoepithelioma of the eyelid is a very rare tumor, which needs to be differentiated from basaloid epithelioma and basal cell carcinoma. Diagnosis is based on clinical and histopathological examination. We present a case of an eyelid trichoepithelioma presenting as a long standing nodule with associated dermatochalasis. Although rare, this entity should be kept in the differential diagnosis of chronic, firm, nodular eyelid lesions.

INTRODUCTION

Solitary trichoepithelioma is rare benign tumor of the hair follicles with eyelid trichoepitheliomas being even rarer with <30 cases reported so far.[12345678910] In a very large series of 83 trichoepitheliomas, Gray and Helwig could find only a single case of solitary eyelid tumor.[1] Although they can present at any age, most common presentations are noted in the 4th decade.[2] Clinical examination alone cannot clinch the diagnosis, and histopathological examination is essential for ruling out other close differential diagnosis of basaloid epitheliomas and basal cell carcinomas (BCC).[123] We present a case of a solitary eyelid trichoepithelioma along with its clinical and histopathological features.

CASE REPORT

A 58-year-old male presented to us with a small, painless, asymptomatic lesion on the right upper lid since 15 years. On examination, the eyelid nodule was 5 mm × 5 mm, firm, nontender, mobile, and not adherent to the overlying skin [Figure 1a]. The eyelid skin had an extra fold secondary to dermatochalasis, however, there was no evidence of any skin ulceration [Figure 1a]. The rest of the ocular examination was unremarkable except for the presence of a right lower lid senile entropion [Figure 1a]. Since the patient was scheduled for an entropion repair, he was also keen for simultaneous excision of the eyelid nodule, which was performed. Postoperative period was uneventful and at the last follow-up, 3 months later, there was no evidence of any recurrence.

Figure 1

Solitary eyelid trichoepithelioma. Clinical photograph of the right eye showing a nodular lesion of the upper eyelid associated with dermatochalasis (a). Microphotograph showing horn cysts with central keratin (H and E ×40), (b), basaloid tumor cells are arranged in the cord and lacy patterns (H and E ×40), (c). High magnification microphotograph showing benign tumor cell admixed in a dense fibrous matrix (H and E ×100), (d)

HISTOPATHOLOGY

Gross pathological examination revealed a grayish white firm mass measuring 5 × 4 × 3 with the cut section being grayish white to grayish yellow without any areas of necrosis or hemorrhages. Microscopic examination showed numerous well-formed horn cysts lined by a thin layer of basaloid cells with a keratin center [Figure 1b]. The tumors comprised of basaloid cells without mitotic figures, forming cords, and lacy strands within a relatively dense matrix of the fibromyxoid stroma [Figure 1c and d]. Inflammatory infiltrate was minimum with no evidence of abnormal hair follicles. The histopathology features were consistent with that of a trichoepithelioma.

DISCUSSION

Trichoepitheliomas are benign tumors that arise from the walls of the hair follicle.[123] They can be classified into three varieties: Solitary, multiple, and desmoplastic.[135] Multiple variants are far more common than the solitary ones. Multiple trichoepitheliomas are usually inherited and maybe associated with Spiegler-Brookler syndrome.[123] Solitary trichoepithelioma does not follow an inheritance pattern and is usually firm, nonulcerated nodule usually <2 cm in diameter. It appears most commonly in middle-aged individuals and most commonly on the face.[4567]

Solitary trichoepitheliomas have frequently been confused with BCC. The distinction between BCC and trichoepithelioma is clinically important since a BCC should be excised with a 3–4 mm margin of healthy tissue, while a trichoepithelioma may only require minimal resection.[12345] Gray and Helwig.[1] in their series of 83 patient showed that 35% of the solitary trichoepitheliomas were misdiagnosed as BCC although they found ulceration to be present in only five of their cases. The presence of ulceration makes the clinician to error toward the diagnosis of either a BCC or sebaceous carcinoma. The histopathological features that go in favor of a trichoepithelioma include numerous keratinous cysts, lacy pattern of tumor cells, dense stroma, minimal inflammation, absent of minimum of abnormal hair follicles. In contrast, a basal cell carcinoma shows epidermal ulceration, very few keratinous cysts, minimal stroma, dense inflammation, and tumor lobules in adenoid and cystic patterns.[12345] Simpson et al.[2] presented the largest study (n = 18) of eyelid trichoepitheliomas over a duration of more than 30 years. There was male preponderance (M: F = 2:1) with the mean age at a presentation being 48.6 years (range 3–73 years). The upper lid was found to be twice more predisposed than lower lids. All patients underwent excision; however, two of them recurred after 10 and 12 years, respectively.

CONCLUSION

Although rare, solitary trichoepitheliomas should be considered in the differential diagnosis of firm, nodular eyelid lesions of middle-aged patients. The careful histopathological examination is mandatory for diagnosis. Although recurrences are rare, all such patient should be kept on a yearly follow-up.