Journal of Cytology
Home About us Ahead of print Instructions Submission Subscribe Advertise Contact e-Alerts Login 
Users Online:1777
  Print this page  Email this page Small font sizeDefault font sizeIncrease font size

LETTER TO EDITOR Table of Contents   
Year : 2009  |  Volume : 26  |  Issue : 3  |  Page : 125-126
Pilomatrixoma: Misdiagnosed as a round cell tumor of soft tissue on fine needle aspiration cytology

Department of Pathology, R G Kar Medical College, Kolkata 700 004, India

Click here for correspondence address and email

Date of Web Publication27-Jan-2010

How to cite this article:
Barui GN, Karmakar R, Sinha A, Bhattacharya A. Pilomatrixoma: Misdiagnosed as a round cell tumor of soft tissue on fine needle aspiration cytology. J Cytol 2009;26:125-6

How to cite this URL:
Barui GN, Karmakar R, Sinha A, Bhattacharya A. Pilomatrixoma: Misdiagnosed as a round cell tumor of soft tissue on fine needle aspiration cytology. J Cytol [serial online] 2009 [cited 2023 Mar 27];26:125-6. Available from:


Pilomatrixoma is a benign tumor of the prickle cell layer of the skin and was first described by Malherbe and Chenantais in 1880. The tumor can cause diagnostic difficulty not only for the clinicians but also for the cytologists. We report one such case that was misdiagnosed as a round cell tumor of the soft tissue.

A 10-year-old girl presented with multiple neurofibroma like swelling all over the body for last two years. The nodules were superficial, firm, and 1-3 cm in size. Fine needle aspiration cytology (FNAC) was performed from one swelling in upper arm of approximately 3 × 2 cm 2 in size. Stained smears were cellular, showing predominantly round to oval cells with scanty cytoplasm. The cells were arranged in sheets; clusters as well as in a discrete manner. Occasional islands of anucleate cells were also seen in the smear [Figure 1]a and b. Diagnosis of 'round cell tumor in the soft tissue' was suggested and excision biopsy advised. Histopathology sections showed islands of two types of epithelial cells, basaloid cells having scanty cytoplasm and pathognomonic shadow (ghost) cells which were anucleate. There were areas of cyst formation, composed of eosinophilic cornified material with foreign body giant cell reaction and calcification. The histopathology diagnosis was 'pilomatrixoma (Malherbe's tumor)'. On review of the smear it was found that basaloid cells of pilomatrixoma were mistaken for round cells of soft tissue tumor and the pathognomonic ghost (shadow) cells had been mistaken as understained cellular clump.

The aspirates have been mistaken for a metastatic carcinoma by the cytologists. [1],[2] Sivakumar [1] in his case had also considered the possibilities of mucoepidermoid carcinoma and calcifying odontogenic tumor. The diagnosis of pilomatrixoma was established only after histopathology. Others have confused the aspirates with basal cell carcinoma. [3]

Most of the lesions diagnosed histopathologically as pilomatrixoma were in the neck region and misdiagnosed in cytology.

Bhadani et al., [4] reported five histologically proven cases of pilomatrixoma. The pre FNAC clinical diagnoses were, sebaceous cyst, tuberculous lymphadenopathy, dermatofibroma, reactive lymphadenopathy, and lipoma. Pilomatrixoma was diagnosed on FNAC in three cases on finding groups of basaloid cells, ghost epithelial cells, pink fibrillary material, and calcium deposit.

Like in our case, Thapiyal et al., [5] misdiagnosed a histologically proven case of pilomatrixoma as a round cell tumor on cytology. The lesion had presented as rapidly growing nodular swelling on the arm.

The risk of misdiagnosing pilomatrixoma as a round cell tumor of soft tissue needs to be kept in mind, especially when the population of shadow cells is low in relation to basaloid cells.

   References Top

1.Sivakumar S. Pilomatrixoma as a diagnostic pitfall in fine needle aspiration cytology. Acta Cytol 2007;51:583-5.  Back to cited text no. 1      
2.Preethi TR, Jayasree K, Abraham EK. A case of pilomatrixoma misdiagnosed as matastatic carcinoma on F N A C. J Cytol 2007;24:207-8.  Back to cited text no. 2    Medknow Journal  
3.Sanyal S, Monickam A, Fine needle aspiration cytology of pilomatrixoma. J Cytol 2004;21:109-10.  Back to cited text no. 3      
4.Bhadani PP, Sen R, Bhadani UK, Karki S, Agarwal S, Is FNAC useful in skin adnexal masses? A study on 5 cases of pilomatrixoma. Indian J Pathol Microbiol 2007;50:411-4.  Back to cited text no. 4  [PUBMED]    
5.Thapiyal N, Joshi U, Vaibhav G, Sayana A, Srivastava AK, Jha RS, et al. Pilomatrixoma mimicking small round cell tumor on fine needle aspiration cytology. Acta Cytol 2008;52:627-30.  Back to cited text no. 5      

Correspondence Address:
Gopi N Barui
Department of Pathology, Flat No. 507, Rail Vihar Co-Op Housing Society, Kolkata - 700 107, West Bengal
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0970-9371.59402

Rights and Permissions


  [Figure 1]

This article has been cited by
1 Cytomorphological spectrum of pilomatricoma A series of 28 cases
Sana Ahuja, Sufian Zaheer
Cytopathology. 2023;
[Pubmed] | [DOI]
2 Novel Mutations in Pilomatrixoma, CTNNB1 p.s45F, and FGFR2 p.s252L: A Report of Three Cases Diagnosed by Fine-Needle Aspiration Biopsy, with Review of the Literature
Cristina Aparecida Troques da Silveira Mitteldorf, Rafael Sarlo Vilela, Melissa Lissae Fugimori, Carla Daniele de Godoy, Renata de Almeida Coudry
Case Reports in Genetics. 2020; 2020: 1
[Pubmed] | [DOI]
3 Pilomatrixoma
Christopher D. Jones,Weiguang Ho,Bernard F. Robertson,Eilidh Gunn,Stephen Morley
The American Journal of Dermatopathology. 2018; 40(9): 631
[Pubmed] | [DOI]
4 Diagnostic pitfalls of pilomatricoma on fine needle aspiration cytology
Gupta, V. and Marwah, N. and Jain, P. and Dua, S. and Gupta, S. and Sen, R.
Iranian Journal of Dermatology. 2012; 15(60): 59-61
5 Fine needle aspiration cytology of pilomatrixoma
Bansal, C., Handa, U., Mohan, H.
Journal of Cytology. 2011; 28(1): 1-6


    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
    Email Alert *
    Add to My List *
* Registration required (free)  

    Article Figures

 Article Access Statistics
    PDF Downloaded165    
    Comments [Add]    
    Cited by others 5    

Recommend this journal