Trichilemmoma arising in the nasal vestibule: report of three cases with special emphasis on the differential diagnosis

Desmoplastic trichilemmoma of the scalp: case report and literature review of immunohistochemical staining features

Desmoplastic trichilemmoma (DT) of the scalp is a rare disease. In this report, we describe a 67-year-old man who had a small papule lesion around the hairline of the left scalp for more than 40 years. The lesion had rapidly grown to become a solitary, round, 15-mm neoplasm within 6 months. Histopathological examination showed that the mass was composed of a peripheral layer of columnar cells with nuclear palisading resembling the outer root sheath; the mass was surrounded by a thickened glassy basement membrane. The stroma in the center of the mass displayed solid, hyaline degeneration and an eosinophilic pattern, streaked with epithelial cords or islands. Immunohistochemical evaluation showed diastase-resistant, periodic acid–Schiff-positive desmoplastic stroma at the center, and Ber-EP4-negative tumor cells (CD34-positive focally and Bcl-2-positive at the periphery). The tumor was completely resected, and no recurrence occurred during the follow-up period. In this report, we also summarize immunohistochemical features from previous reports of DT, facilitating differential diagnosis of DT from some invasive skin tumors.

Challenges in the diagnosis of cutaneous adnexal tumours

The diagnosis of cutaneous adnexal neoplasms, a heterogeneous group of entities, is often perceived by practising pathologists as challenging. A systematic approach to diagnosis is necessary for classification of these lesions, which establishes the tumour differentiation (follicular, sebaceous, sweat gland or apocrine) and evaluates histological features differentiating between benign and malignant entities. Consideration of clinical history is a necessary adjunct in evaluation of the adnexal neoplasm, as characteristic anatomical sites are described for many adnexal lesions. In some instances, immunohistochemical studies may also be employed to aid the diagnosis. The differential diagnosis between primary cutaneous adnexal neoplasms and cutaneous metastases from visceral tumours may also be difficult. Clinical, radiological, histological and immunohistochemical characteristics will be further discussed, considering that the correct diagnosis has a significant impact on the patient's management and prognosis.

Linear trichilemmoma following a blaschkoid pattern: a clinical dilemma

BACKGROUND

Trichilemmoma are benign adnexal neoplasm with follicular outer sheath differentiation. It usually appears as single or multiple papules that resembles colour of the surrounding skin. They are most commonly seen on the face particularly on the nose and cheek.

OBJECTIVES

We report a case of linear trichilemmoma following blaschkoid pattern.

METHODS

A 13 year old boy presenting with asymptomatic plaque on the right side of the nose was fully evaluated for possible cause.

RESULTS

On histopathology, a diagnosis of trichilemmoma was made.

CONCLUSION

This is the first case report where linear trichilemmoma following a blaschkoid pattern is seen.