Pilomatrixoma – Presented as Hypopigmented Tender Nodule: Diagnosed by FNAC: A Case Report with Review of Literature
An 18-year-old girl presented to the surgical outpatient department with complaints of tender swelling over left mid-arm of one-year duration. The swelling gradually increased in size to attain present size. We received requisition for cytological examination with clinical probable diagnosis of neurofibroma. On inspection, swelling measured 3 × 2 cm, seen over left arm with overlying skin showing atrophic changes and hypopigmentation, giving an appearance of a small patch of vitiligo []. There was no history of trauma. There was also no history of topical application of any steroids or other medications. On palpation, swelling was firm to hard, tender, mobile, and situated in the subcutaneous plane.\nFNA was carried out, and all slides were issued to junior and senior faculties in the department of pathology for their independent opinion and discussion. Different diagnoses were obtained like giant cell tumor of tendon sheath, epidermal inclusion cyst with giant cell reaction, granulomatous inflammatory lesion, basi-squamous carcinoma, and pilomatricoma were obtained. The smears studied revealed cell-rich aspirate containing predominantly basaloid cells in tight clusters, scattered squamous cells and anucleate squames, shadow cells, plenty of multinucleated giant cells [], and focal areas of calcification. In view of presence of all the diagnostic criteria required to diagnosis pilomatrixoma were present, we offered final diagnosis of PMX and requested for excision and histopathological confirmation. The tumor was excised and sent.\nGrossly, the tumor measured 3 × 2 cm, well-encapsulated, nodular, with surface showing multiple chalky white powdery deposits scattered throughout []. The tumor was gritty to cut, showed powdery, chalky white areas of calcification. Slices were decalcified in decalcifying solution, and sections were prepared and stained with hematoxylin and eosin. Histopathological examination revealed encapsulated tumor mass, composed of nests of peripheral basaloid cells admixed with squamous cells showing transition phase to anucleate squamous cells and then to ghost cells [Figures and ]. The stroma showed multinucleated foreign body type of giant cell response [] to the tumor keratin. Focal areas of calcifications were also seen. All the features correlated with cytological findings, and diagnosis of PMX was issued. The patient is asymptomatic during post-operative follow up with no local recurrence.