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Year : 2016  |  Volume : 9  |  Issue : 3  |  Page : 370-373  

Pilomatrixoma of right scapular region: Rare case report

Department of Pathology, Prathima Institute of Medical Sciences, Karimnagar, Andhra Pradesh, India

Date of Web Publication17-May-2016

Correspondence Address:
Srikanth Shastry
Department of Pathology, Prathima Institute of Medical Sciences, Karimnagar, Andhra Pradesh
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0975-2870.182510

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Pilomatrixoma, a benign skin appendageal tumor, is seen commonly in head and neck. Pilomatrixoma also known as pilomatricoma or calcifying epithelioma of Malherbe. These lesions are typically found in the head and neck region, but also occur in the upper extremities and are rarely reported in other sites. Most cases of pilomatrixoma occur in children under the age of 7 and the condition is twice as common in females as in males. Pilomatrixomas are frequently misdiagnosed when the evaluation is based on clinical or radiographic examination alone. Therefore, the final diagnosis requires histopathological examination.

Keywords: Calcifying epithelioma of Malherbe, pilomatrixoma, right scapular swelling

How to cite this article:
Kashif MM, Shastry S. Pilomatrixoma of right scapular region: Rare case report. Med J DY Patil Univ 2016;9:370-3

How to cite this URL:
Kashif MM, Shastry S. Pilomatrixoma of right scapular region: Rare case report. Med J DY Patil Univ [serial online] 2016 [cited 2023 Feb 5];9:370-3. Available from:

  Introduction Top

Pilomatrixoma is a rare, benign tumor that originates in the cells of the hair follicle matrix. [1] As reported by Lan et al, [2] the tumor was first described by Malherbe and Chenantais and it was believed to arise from the sebaceous gland. In 1922, Dubreuilh and Cazenave described its unique histopathology consisting of basaloid cells and shadow/ghost cells. In 1942, Turhan and Krainer determined that the origin of this neoplasm is from hair cortex cells. [3] Later, the term pilomatrixoma was coined by Forbis and Helwig in 1961, thus, avoiding the term epithelioma which carries the connotation of malignancy and it was suggested that the cells of origin are the outer root sheath cells of the hair follicle. [1]

The purpose of this article is to illustrate the diagnostic pitfalls encountered in these cases and to review the literature with special emphasis on the diagnostic features and differentials in order to better familiarize the clinicians with this entity.

  Case Report Top

A 54-year-old lady presented with a nodular mass on the right scapular region. The lesion was first noticed by the patient three months back; it had gradually increased in size during the last 15 days. Physical examination revealed a cystic nodule measuring 7 cm × 4 cm in size. Initially, the swelling was small and increased to the present size. The overlying skin showed red discoloration with prominent vessels. The patient gave no history of pain or trauma. On examination, the swelling was elastic and hard. The surface of the mass was coarsely granular and mobility was good. The tumor was distinctly demarcated from the surrounding tissue. There were no palpable lymph nodes in the cervical region. Family history was unremarkable. Clinically, it was diagnosed as soft tissue tumor or any cystic lesion. The patient underwent surgery for the same and the specimen was sent to the pathology department.

Grossly, the specimen was skin covered, hard, and irregular mass measuring 7 cm × 4 cm × 2 cm. A gritty sensation was felt while cutting the specimen. The cut surface of the nodule was whitish and variegated in appearance [Figure 1]. Multiple sections were taken and it was confirmed as pilomatrixoma on microscopy.
Figure 1: Gross showing tumor of size 7 cm × 4 cm × 2 cm, irregular and nodular (a) Cut section is showing whitish and variegated areas (b)

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  Discussion Top

Pilomatricoma is an asymptomatic slowly growing benign cutaneous tumor, differentiating toward the hair matrix of the hair follicle. It is covered by normal or hyperemic skin and usually varies in size from 0.5 to 3 cm. It is found particularly on the head and neck region (over 50% of cases) with a female predominance. [4] Other locations include the upper extremity, trunk, and lower extremity in decreasing order of frequency. Pilomatricomas usually are asymptomatic (pain appears only with associated inflammation and ulceration); deeply seated, firm, nontender subcutaneous masses adherent to the skin but not fixed to the underlying tissue. Stretching of the skin over the tumor shows the "tent sign" with multiple facets and angles, a pathognomonic sign for pilomatricoma. In addition, pressing on one edge of the lesion causes the opposite edge to protrude from the skin like a "teeter-totter." Both these "tent sign" and "teeter-totter sign" are the most helpful clinical clues to the diagnosis of pilomatricoma. Another characteristic feature of pilomatricoma is the blue red discoloration of the overlying skin which definitely excludes the possibility of epidermal inclusion or dermoid cyst. This characteristic clinical feature was overlooked in both these cases. Another feature overlooked in the first case was that the lesion was adherent to the skin but otherwise not fixed to the underlying tissues.

Occasionally, there may be a history of previous trauma although this association is unusual. Finally, pilomatricoma can be associated with other diseases such as myotonic dystrophy, Gardner syndrome, Steinert's disease, Turner syndrome, and sarcoidosis. [5]

Histopathologically, pilomatricoma consists of lobules and nests of epithelial cells composed of two major cell types: Basophilic cells and eosinophilic shadow cells [Figure 2] and [Figure 3]. Early lesions show a predominance of basophilic cells grouped in islands at the tumor periphery. With tumor maturation, the basophilic cells acquire more cytoplasm and gradually lose their nuclei to become eosinophilic shadow cells [Figure 4]. These latter cells constitute the central portion of the tumor and frequently calcify [Figure 5]. Gradually, this calcified foci increase imparting the bony hard consistency to the lesion.
Figure 1: Gross showing tumor of size 7 cm × 4 cm × 2 cm, irregular and nodular (a) Cut section is showing whitish and variegated areas (b)

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Figure 3: Section is showing pilomatrixoma with both basophilic and shadow cells ([a] H and E, ×10, [b] H and E, ×40)

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Figure 4: Section is showing basophilic and shadow cells ([a] H and E, ×10, [b] H and E, ×40)

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Figure 5: Section is showing both basophilic and shadow cells with focal areas of calcifi cation in the center ([a] H and E, ×10, [b] H and E, ×40)

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Four distinct morphological stages of pilomatricoma are defined as:

  1. Early - Small and cystic lesions,
  2. Fully developed - Large and cystic,
  3. Early regressive - Foci of basaloid cells, shadow cells, and lymphocytic infiltrate with multinucleated giant cells,
  4. Late regressive - Numerous shadow cells, absence of basaloid and inflammatory cells, calcification and ossification may be present.
It is important to note, however, these ghost cells, though quite specific, are not unique to pilomatrixomas. There may be a variably prominent inflammatory reaction. Foreign body giant cells, keratin debris, and central calcifications are also characteristic. Calcification has been noted in 70-85% of cases.

Diagnostic imaging is generally not obtained in the evaluation of pilomatrixomas as they are usually superficial, small, and well-circumscribed. Plain radiographs, in this case, were unremarkable, but pilomatrixomas may demonstrate foci of calcification. Computed tomography demonstrates a sharply demarcated, subcutaneous lesion of soft tissue density, with or without calcification. Magnetic resonance imaging may reveal a rim-enhancing lesion with small areas of signal dropout which may be consistent with calcifications. Ultrasound demonstrates a well-defined mass with inner echogenic foci and a peripheral hypoechoic rim or a completely echogenic mass with strong posterior or acoustic shadowing in the subcutaneous layer.

A rare malignant counterpart, pilomatrix carcinoma, has been described and approximately 90 cases have been reported in the literature. It is locally aggressive and can recur. In several cases, it has demonstrated metastases. Many key features are similar between these benign and malignant counterparts; the primary differentiating characteristics include a high mitotic rate with atypical mitoses, central necrosis, infiltration of the skin and soft tissue, and invasion of blood and lymphatic vessels.

Pilomatrixoma show positive for cytokeratin, CD3, CD20, CD68, PCNA, and CD3411.

The treatment of pilomatrixoma is complete excision. In general, adhesion to the surrounding tissue is not very dense and resection is technically easy.

To conclude, the present case highlights the importance of considering pilomatrixoma in the clinical and pathologic differential diagnosis of dermal or subcutaneous nodule even in locations other than head and neck region. The recurrence rate is low, ranging from 0-3%. If a lesion recurs after excision or rapidly enlarges, it should be excised due to malignant potential or possible misdiagnosis.


We are thankful to Mr. G. V. S. N. Malleswara Rao for his help in grossing and staining.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Reddy SS, Gadre SA, Adegboyega P, Gadre AK. Multiple pilomatrixomas: Case report and literature review. Ear Nose Throat J 2008;87:230-3.  Back to cited text no. 1
Lan MY, Lan MC, Ho CY, Li WY, Lin CZ. Pilomatricoma of the head and neck: A retrospective review of 179 cases. Arch Otolaryngol Head Neck Surg 2003;129:1327-30.  Back to cited text no. 2
Kaveri H, Punnya A. Pilomatricoma: A dermal analog of calcifying odontogenic cyst. Indian J Dent Res 2008;19:261-3.  Back to cited text no. 3
[PUBMED]  Medknow Journal  
Yencha MW. Head and neck pilomatricoma in the pediatric age group: A retrospective study and literature review. Int J Pediatr Otorhinolaryngol 2001;57:123-8.  Back to cited text no. 4
Barberio E, Nino M, Dente V, Delfino M. Guess what! Multiple pilomatricomas and Steiner disease. Eur J Dermatol 2002;12:293-4.  Back to cited text no. 5


  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]

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