Pilomatricoma: Diagnosed by fine needle aspiration cytology
Pavneet Kaur Selhi, Puneet Singla, Vikram Narang, Harpreet Puri
Department of Pathology, Dayanand Medical College and Hospital, Ludhiana, Punjab, India
Vikram Narang
Department of Pathology, Dayanand Medical College and Hospital, Ludhiana, Punjab
Selhi PK, Singla P, Narang V, Puri H. Pilomatricoma: Diagnosed by fine needle aspiration cytology. Indian J Dermatopathol Diagn Dermatol 2014;1:45-6
Selhi PK, Singla P, Narang V, Puri H. Pilomatricoma: Diagnosed by fine needle aspiration cytology. Indian J Dermatopathol Diagn Dermatol [serial online] 2014 [cited 2020 Jan 19];1:45-6. Available from: http://www.ijdpdd.com/text.asp?2014/1/1/45/135199
Pilomatricomas, formerly known as pilomatrixomas, are relatively uncommon, benign tumors arising from skin adnexa. Despite being better defined, pilomatricomas continue to be frequently misdiagnosed and are not usually included in the differential diagnosis. We report a case of pilomatricoma in a 16 year old girl who presented with a subcutaneous swelling in neck and in whom the diagnosis was made on fine needle aspiration cytology (FNAC).
A 16-year-old girl presented to our outpatient department with a nodular neck swelling measuring 1.5 × 1 cm, since 6 months. Examination revealed a non-tender, firm and mobile nodule with reddish to purple skin discoloration. Fine needle aspiration cytology (FNAC) was advised with a clinical suspicion of reactive lymphadenopathy. Cytology smears were cellular with clusters of tightly packed cells having vesicular nuclei, presence of nucleoli, and moderate amount of basophilic cytoplasm exhibiting mild cytological atypia associated with anucleate ghost cells. [Figure 1],[Figure 2] and [Figure 3] Hence, the possibility of pilomatricoma was suggested.
Figure 1: Vacuolated ghost cells (arrow) (Giemsa ×100)
Figure 2: Basaloid cells (Giemsa ×200)
Figure 3: Multinucleated giant cells (Giemsa ×400)
Histopathological examination of the excision biopsy revealed basaloid cells and anucleate shadow cells (ghost cells) along with multinucleate giant cells, thus, confirming the diagnosis of pilomatricoma [Figure 4].
Figure 4: Paraffin section showing basaloid cells and ghost cells. (Hematoxylin and Eosin ×200)
On follow-up, patient responded well and no local recurrence has been noted.
Pilomatricoma is ectodermal in origin as it arises from hair germinal matrix. It represents a disturbance of hair follicle cycle in which limited cytologic differentiation of pilar keratinocytes occurs but further development into mature hair does not happen. [1],[2],[3] It can occur at any age with female preponderance but demonstrates a bimodal peak during first and sixth decades of life. Radiological imaging is of limited diagnostic value for pilomatricoma as it only shows variable amount of calcification. [4],[5]
FNAC is useful in preoperative diagnosis. Presence of ghost or shadow cells is a must for the diagnosis. Histopathologically, it shows sharply demarcated dermal nodules surrounded by a capsule of compressed fibrous tissue located in the lower dermis and extending into subcutaneous fat. Shadow cells or ghost cells evolve from basaloid cells. Basaloid cells predominate in the early lesions; and as the lesions mature, shadow cells become more prominent in the center. Calcification and ossification is frequently present in these cells ranging from 69% to 85% in most series. [3],[4],[5]
Only few cases of malignant transformation of pilomatricoma have been reported till date in the literature. Histologic features include proliferating basaloid cells with atypical mitosis, nuclear pleomorphism, vascular invasion, and infiltration in underlying tissues. No malignant transformation was seen in the present case. [3],[4],[5]
Treatment of choice is wide local excision with 1 to 2 cm of healthy skin margins to minimize the risk of local recurrence. The reported risk of recurrence after surgery is 0% to 3% in most of the series. Repeated recurrence is indication of malignant transformation. [3],[4],[5]
To summarize, pilomatricoma is an asymptomatic, slow growing, firm, non-tender, and benign skin tumor that originates from hair follicle matrix cells and is mainly present in children and young adults. With all these clinical features, morphological, cytological and pathological findings, diagnosis of pilomatricoma should always be considered.
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Selhi PK
Singla P
Narang V
Puri H