Pilomatrixoma arising from maxillary sinus - First of its kind.

Dear Editor,

Pilomatrixomas are uncommon tumors, which arise due to uncontrolled proliferation of hair matrix cells. They are said to represent 0.001%–0.003% of all dermatopathologic specimens.[1] Head and neck is the most common site. PubMed data search shows no data on pilomatrixoma of the nasal cavity or paranasal sinuses. Hence, this is the first reported case of pilomatrixoma involving the nasal cavity and maxillary sinus.

A 34-year-old male patient presented with progressive nasal obstruction and mass in the left nasal cavity for the past 6 months. It was associated with rhinorrhea and hyposmia. There was no history of pain, fever, epistaxis, trauma, or nasal surgery. He was on fluticasone furoate nasal spray. On examination, a pale-pinkish mass was seen filling the left nasal cavity, extending up to the anterior nares, with ulcerations on the exposed surface [Figure 1].

Figure 1

Clinical photograph showing left-sided nasal mass

It was firm, nontender, not bleeding on touch and was arising from the lateral wall. Posterior rhinoscopy showed pinkish mass at the left choana, rest is normal. Nasal endoscopy showed the deviation of the septum to the right side, and mass arising from the left middle meatus. Computed tomography (CT) showed homogenous mass filling left nasal cavity and left maxillary sinus, extending up to the choana. Under general anesthesia, the mass of 7.5 cm was excised endoscopically. Attachment to the posterior maxillary wall was removed with microdebrider. The histopathologic examination showed outer respiratory epithelium, below which was stratified squamous epithelium. It had large areas showing shadow cells, multinucleated giant cells, areas of calcifications, small clusters of basaloid cells with dense chronic inflammatory (lymphoplasmacytic) infiltration suggestive of nasal pilomatrixoma [Figure 2]. The patient is on follow-up with no evidence of any recurrence.

Figure 2

Histopathology picture showing ghost cells and clusters of basaloid cells suggestive of nasal pilomatrixoma

Pilomatrixoma or calcifying epithelioma of Malherbe is a benign tumor that arises from hair follicles, first described by Malherbe and Chenantais in 1880.[2] The term pilomatrixoma was coined by Forbis and Helwing in 1961. The most common site is the head and neck, followed by the limbs. Nose, however, is a very rare site. Since there are no hair follicles in the maxillary sinus, this case becomes an interesting one. Pilomatrixoma has a female preponderance. It is common in first two decades of life.

The exact etiology of pilomatrixoma is still unknown. Mutation of the β-catenin gene and viral etiology are suggested. It presents as a slowly growing, painless subcutaneous or intradermal mass, which is firm and gritty to palpation and mobile. It can stretch the skin over it, producing a “tent sign.” Their usual size ranges from 1 cm to 3 cm. However, here, it was quite large, 7.5 cm. They have an association with Gardner's syndrome, Myotonic dystrophy, Turners syndrome, and Xeroderma pigmentosum. In CT, sand-like or nodular calcifications may be seen. Malignant transformation occurs very rarely, termed as pilomatrix carcinoma. Jones et al. reported that only 16% of pilomatrixomas are accurately diagnosed clinically.[3] Treatment is complete excision, and recurrence is rare.

Pilomatrixoma is a rare tumor of the hair follicles. This case adds a new site to this peculiar lesion, the nasal cavity and sinus.

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