Pilomatricoma in the Upper Extremity after Vaccination: A Case Report

Abstract

Pilomatricoma (also known as pilomatrixoma) is a rare benign skin tumor arising from hair follicle stem cells; it is also known as calcifying epithelioma of Malherbe. A definitive diagnosis can be made by histopathological examination. Surgical excision of the lesion is recommended for its treatment. The lesion can often be misdiagnosed when differential has not been considered. In the literature, there are few reports of pilomatricoma cases occurring after vaccination. A 21-month-old male patient was admitted to our clinic with a mass on his left arm that occurred after vaccination. The lesion was completely excised. The diagnosis of pilomatricoma was made after histopathological examination. As there were no predisposing factors other than vaccination, we concluded this to be a complication of the vaccination. The pathogenesis of pilomatricoma is unclear, but inflammation and trauma may promote neoplastic development. We report this case to draw attention to this rare lesion and to the possible etiopathogenetic association of vaccination with pilomatricoma.

Pilomatricoma on the Sole Following Wart Treatment

“…Pilomatricoma presents as a solitary nodule and often occurs in the head and neck or the upper extremities 6 . Lower limbs are uncommon sites for pilomatricoma and the incidence of pilomatricoma on lower extremities was reported as 2%, 5%, and 9% 2 7 8 .…”

“…Unfortunately, we did not perform genetic studies in the patient. Second, trauma and infection are suspected to contribute to pilomatricoma development 6 . Hemorrhage followed by trauma, such as injection, can promote the growth of pilomtricoma 5 .…”

Pilomatricoma Growing at the SARS-CoV-2 mRNA Vaccination Site

“…Although the exact cause is unclear, it has been linked to trauma. [ 2 5 7 ] Reports of pilomatricoma with a history of preceding vaccine[ 2 4 5 7 10 11 12 13 ] or drug injection[ 3 14 ] are summarized in Table 1 . Eight of these are associated with different vaccines and two with injectable drugs.…”

“…[ 4 8 ] Tumour development may also be influenced by persistent inflammation, wound healing or the inoculated agent. [ 2 4 5 7 8 ] Previous reports have discussed ecchymotic reactions, persistent vaccine reactions after BCG vaccination and injection site reactions that proceed to severe erythema on the arm [ Table 1 ]. Our patient also reported erythema at the injection site 2–3 weeks after the second dose of immunisation which can be described as a delayed-type localised hypersensitivity reaction possibly due to vaccine excipient.…”

“…[ 1 ] PMs are usually asymptomatic and often located on the head and neck region and upper extremities but can rarely occur on the chest, trunk or lower extremities. [ 2 3 4 5 6 7 8 ] There have been several cases of pilomatricoma documented after various immunisations. Here, we present a case of pilomatricoma that grew at the vaccination site after BNT162b2 mRNA vaccine (Pfizer-Bionthec).…”