From a dermatologist to a laryngologist, that is pilomatrixoma of earlobe

Introduction

Pilomatrixoma, or Malherbe’s calcifying epithelioma, is a benign neoplasm formed from hair matrix cells. It mainly occurs in the head, neck and upper torso area, although it can occur anywhere on the skin where hair follicles are located [1, 2]. It is a hard, subcutaneous, non-painful lesion, usually reaching 1 to 5 cm in diameter. Lesions greater than 5 cm in diameter are called giant calcifying epitheliomas [3]. Most commonly, pilomatrixoma is covered with unchanged skin, rarely with reddish-blue skin discolouration and ulceration [4]. There are 2 disease peaks for pilomatrixoma: under 20 years of age and at 50–-65 years of age. Pilomatrixoma is observed with higher frequency in the female sex.

Case report

The patient, a 31-year-old female, was referred to the Department of Otolaryngology and Laryngological Oncology by a dermatologist because of an enlarging lesion of the left auricle for more than 6 months (Figure 1). Previous dermatological treatment included topical keratolytic drugs and cryotherapy, without success. Due to the progression of the tumor (Figure 2), the patient presented to the ENT clinic, where a section of the tumour was taken for histopathological examination. The histopathological examination resulted pilomatrixoma. In view of the diagnosis, it was decided to qualify the patient for surgical treatment of the lesion under local anaesthesia. The lesion was removed with a margin of healthy tissue and the defect was filled by moving the mobilized auricle skin. The healing process was without complications and the patient was satisfied with the final aesthetic result of the procedure (Figure 3). During the patient’s follow-up at the ENT clinic for over a year, no recurrence of the lesion was observed.

Discussion

Pathophysiology of pilomatrixoma is suspected to involve mutations in exon 3 of the B-catenin gene (CTNNB1), which is involved in hair follicle differentiation. Overexpression of B-catenin results in matrix cell proliferation [5]. Pilomatrixoma is a benign tumour; although there are cases of transformation to malignant pilomatrix carcinoma [6]. There are pilomatrixoma, proliferative pilomatrixoma and malignant pilomatrixoma types. Pilomatrix carcinoma can develop de novo or undergo neoplastic transformation from pilomatrixoma [7]. Histopathological examination is crucial, in which pilomatrix carcinoma is characterised by a predominance of basaloid cells, tumour necrosis and also perivascular and lymphoid invasion [8]. Three cell types can be observed in the pilomatrixoma tissue: basaloid cells occurring peripherally, ‘shadow cells’ centrally and intermediate cells in between [6]. Pilomatrixoma usually occurs as a single lesion, multiple tumours can be seen in cases of myotonic dystrophy, sarcoidosis, Gardner syndrome [9]. The treatment of choice is radical surgical removal of the tumour. No cases of spontaneous regression of pilomatrixoma have been reported [10]. The recurrence rate is between 2% and 6% and may be due to incomplete resection of the lesion. Malherbe’s calcifying epitheliomas resemble other skin lesions so the differential diagnosis should involve a sebaceous cyst, epidermoid cyst, epitheliomas, neurofibromas, foreign body reaction, calcified cysts or haemangiomas, cartilage, fibrosarcomas, osteoma cutis and giant cell tumour among others [5].

Funding

No external funding.

Ethical approval

Not applicable.

Conflict of interest

The authors declare no conflict of interest.

References