International Journal of Trichology

: 2013  |  Volume : 5  |  Issue : 4  |  Page : 190--193

Cyto-histopathological and clinical correlation of pilomatricomas: A 4 year study

Afiya Shafi, Ather Hafiz Khan, Shazia Bashir, Mohsin ul Rasool, Shaveta Sharma, Abdul Rasheed 
 Department of Pathology, SKIMS Medical College, Bemina, Srinagar, Jammu and Kashmir, India

Correspondence Address:
Ather Hafiz Khan
Department of Pathology, SKIMS Medical College, Bemina, Srinagar, Jammu and Kashmir


Aim: The aim of the following study is to characterize the cytological features of pilomatricomas (PMXs) on fine-needle aspiration (FNA) and correlate with the histopathological features. Materials and Methods: FNA, histopathological and clinical diagnosis of 12 cases of PMXs were analyzed. Clinical, aspiration findings and histopathological features were correlated with histopathological diagnosis which was taken as the gold standard. A written consent was taken from patients or parents as appropriate. Morphological features of both aspiration as well as histopathological features were graded. The study was duly approved by the Hospital Scientific Review Committee. Results: Out of the 7600 cases studied retrospectively over a period of 4 years, only 12 cases were diagnosed as PMXs. These tumors were mainly located in the head and neck region and mostly affected young females (median age 9.5 years). The mean size of these lesions was 0.9 cm. Out of the 12 histopathologically proven cases of PMX, the correct clinical diagnosis was given in only one case while cytopathological diagnosis was achieved in four cases. Conclusion: PMX is a rare tumor, which is mostly found in the pediatric age group. The clinical features should be keenly observed. Keeping in mind the diagnostic pitfalls a cytopathologist may encounter, histopathology should be regarded as the gold standard for diagnosis.

How to cite this article:
Shafi A, Khan AH, Bashir S, ul Rasool M, Sharma S, Rasheed A. Cyto-histopathological and clinical correlation of pilomatricomas: A 4 year study.Int J Trichol 2013;5:190-193

How to cite this URL:
Shafi A, Khan AH, Bashir S, ul Rasool M, Sharma S, Rasheed A. Cyto-histopathological and clinical correlation of pilomatricomas: A 4 year study. Int J Trichol [serial online] 2013 [cited 2020 Jul 6 ];5:190-193
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Pilomatricoma (PMX) also known as calcifying epithelioma of Malherbe or pilomatrixoma was first described as "epithelioma cutis necrotic calcification Malherbe" by Malherbe and Chenantais [1] in 1880 as a benign, subcutaneous tumor arising from sebaceous glands. However, the term pilomatrixoma now called PMX was proposed by Forbis and Helwig [2] in 1961, thus avoiding the word epithelioma, which may erroneously be described as malignancy by some.

PMX is an uncommon tumor, which is sparsely reported in literature and is limited to a few case reports. The purpose of this study is to better describe the diagnostic features of this skin tumor cytologically and correlate these findings with histopathology in order to familiarize the clinicians with this uncommon entity.

 Materials and Methods

The present study was conducted in the Department of Pathology in our institute retrospectively over a period of 4 years. Out of the total 7600 cases only 12 were diagnosed as PMX emphasizing the rarity of this benign yet an uncommon tumor. All of these lesions were superficially located with bluish discoloration [Figure 1] and adherent to overlying skin, non-tender, firm too hard on palpation with the duration of <8 months in all cases. Fine-needle aspiration cytology (FNAC) was performed in all cases using a 23-guage needle attached to a 20 ml disposable syringe. The slides prepared were air-dried for May-Grunwald-Giemsa and wet fixed for H and E staining using the standard staining procedures. All the surgical biopsies were fixed in 10% buffered formalin, routinely processed and embedded in paraffin. Blocks were sectioned at 4 µ thickness. Sections were stained with H and E.{Figure 1}

Cytological and histopathological features such as the presence of basaloid cells, shadow cells, giant cells and calcified deposits were studied in detail in each case separately. Histopathological diagnosis was considered final and cytological findings were reviewed that were missed on cytology.


All the relevant clinical data including were obtained from the medical records for each case and documented on Microsoft excel sheet. Data analysis was performed with Statistical package for social science (SPSS) for Windows Software Package (SPSS), release 17, Chicago, USA.


In our study, out of the 7600 cases, only 12 cases were diagnosed as PMXs constituting 0.15% of the total cases emphasizing the rarity of this tumor. Moehlenbeck [3] reviewed 140,000 skin tumors and noted that PMX represented 0.12% of these cases. The median age of the presentation was 9.5 years (mean age 13.58 years) with age ranging from 3 to 58 years. There was a definite female preponderance (3:1). Out of the 12 cases, the most common site of predilection was head and neck (7/12), followed by the upper limb (4/11). Only 1 case showed lower limb involvement. Size of the lesions varied from 0.4 to 1.2 cm (mean 0.9 cm) with the largest lesion measuring 1.2 cm located on the right thigh and the smallest lesion measuring 0.4 cm located on the forehead.

Several characteristics were studied on cytology [Figure 2] including the presence of aggregates of small cells having high nucleocytoplasmic ratio (basaloid cells), cells with eosinophilic cytoplasm with a central clear area (shadow cells), giant cells, squamous cells and calcium deposits. Basaloid cells (6/12) were the most persistent findings in most cases followed by shadow cells (4/12) [Graph 1]. Presence of calcification was seen in 50% of the cases on cytology.{Figure 2}


Two cases showed only presence of macrophages leading to an erroneous diagnosis of a benign cystic lesion while in 2 cases FNAC was non-contributory owing to a cellularity, which may have been due to the presence of calcium deposits [Table 1].{Table 1}

The most persistent histopathological findings in all cases were the presence of basaloid and ghost cells with areas of apparent evolution from the former to the latter [Figure 3]. Correct clinical diagnosis was given in only one case further emphasizing the need to incorporate this lesion in the differential diagnosis. The cytological diagnosis was reached in only four cases, whereas on histopathology, all cases conformed with the histological features of a PMX. Cytology was reviewed and occasional shadow cells and basaloid cells were seen which were earlier missed.{Figure 3}


In this series of PMX, the median age of the presentation was 9.3 years with one patient presenting at the age of 58 years. Lan et al. [4] in his study concluded that PMXs is a disease of the children affecting the age group of 1-20 years. Julian et al. [5] in their study observed bimodal presentation of PMX in 1 st and 6 th decades of life. Our study showed a female preponderance (3:1) which is in consonance with the majority of other studies on PMX. [6],[7]

The most frequent anatomical location for PMX is the head and neck region followed by the upper extremities, trunk and the lower extremities. [8] Involvement in the face has been reported in cheek, preauricular, periorbital, frontal and temporal areas. [6]

Majority of these lesions are clinically misdiagnosed. This was seen in our study also as these lesions were misdiagnosed clinically as epidermal inclusion cyst, monomorphic adenoma and benign cystic lesion or as benign fibrous histiocytomas. This can be attributed to lack of familiarity with this uncommon tumor. Clinically these lesions can be suspected based on two pathognomonic signs - "the tent sign" [9] in which the stretching of the overlying skin causes multiple facets and angles of the lesion and "the teeter-totter sign" [10] in which pressing of one edge of the lesion causes the other edge to protrude from the skin.

In our study, all the cases were solitary lesions although multiple occurrences and familial cases are also known in a small percentage of patients generally in association with disorders such as Gardner syndrome, Steinert disease, sarcoidosis, Rubinstein-taybi syndrome and Turner syndrome. [4]

Radiographic imaging is of little diagnostic value in PMX. [4] The role of FNAC as a pre-operative diagnostic investigation has been described. In our study, the characteristic cytological features were graded using a scale of +1 to 3+ as was done by Bansal et al. [11] Only 4 cases (33.33%) were correctly diagnosed on FNAC showing varying proportions of most of the described characteristic cytological features, which is a little lower than as seen in other studies. [12],[13],[14] Two cases on FNA revealed cystic macrophages only based on which a presumptive diagnosis of a benign cystic lesion was made. Cystic change is known in early PMX in evolutionary stage. [15]

The cause of the misdiagnosis could be attributed to the absence of ghost cells, dominance of squamous cells, interobserver variability and calcified nature of the lesion and also due to inadequate sampling. The definitive diagnosis is achieved in almost all cases by histopathologic examination. [16] This was true in our study as well in which all of the cases were correctly diagnosed on histopathology. Histopathologically, PMX is seen in nests composed of two cell types - basaloid cells and shadow cells. Shadow cells are a result of tumor maturation resulting due to loss of nuclei and acquiring the central area of the lesion, which may later calcify imparting firm to hard consistency.


PMX is a rare tumor, which is mostly found in the pediatric age group. The lesion should be included in the differential diagnosis while examining superficial lesions in this age group mostly in the head and neck region. The main purpose of this article is to raise awareness among clinicians and also to highlight the cytological features of this benign tumor, the diversity of which may prove to be a diagnostic pitfall for the cytopathologists.


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