|Year : 2013 | Volume
| Issue : 1 | Page : 37-38
An unusual presentation of pilomatrixoma
Department of General Surgery, Jawaharlal Nehru Medical College, Belgaum, Karnataka, India
|Date of Web Publication||28-Mar-2013|
H No 39, 2nd Main, 2nd Cross, Sadashivnagar, Belgaum, Karnataka
Source of Support: None, Conflict of Interest: None
The case reported here is an 18 year old male. He complained of a painless lump located on the left cheek over the anterior surface of masseter muscle for last 2 years. An early diagnosis of sebaceous cyst was made. Excision was performed and histopathological findings revealed pilomatrixoma. Pilomatrixoma is an uncommon, harmless, skin lesion derived from hair matrix cells. It is composed of an epithelial component of the most proximal portion of hair follicle. It is most often diagnosed in young children but may also affect adults. Single skin coloured or purplish lesions arise on the head and neck, but they may occur at any site. The key to diagnosis is identification of darkly stained 'basophilic cells' and 'shadow cells'. Calcium deposits are found in most of the lesions. Complete surgical excision is the treatment with rare chances of complications.
Keywords: Calcium, pilomatrixoma, treatment
|How to cite this article:|
Hombal P. An unusual presentation of pilomatrixoma. J Sci Soc 2013;40:37-8
| Introduction|| |
Pilomatrixoma is the most common type of pilar tumors,  most frequently appearing in the first or second decade of life. The tumor is usually a deep-seated, solitary, firm nodule with overlying normal epidermis.  This is a rare, benign, circumscribed, calcifying epithelial neoplasm that is derived from hair matrix cells. However, multiple pilomatrixomas are uncommon. 
| Case Report|| |
An 18-year-old male presented in the Department of General Surgery, KLE Hospital, Belgaum, with the complaint of a painless lump on his left cheek over the anterior surface of masseter muscle for the last 2 years. The swelling was round, 3-4 cm in diameter, initially being superficial but subsequently involved the deeper tissues. It was not associated with any pus or discharge [Figure 1]. A diagnosis of calcified sebaceous cyst/acne cyst was established. Physical examination revealed that the lump was hard, non-tender, 3 × 3 cm (approximately) in size, and adherent to the overlying skin. He had no other signs or symptoms, and his routine laboratory tests were normal. A preliminary diagnosis of sebaceous cyst was made and excisional biopsy of the lump was performed preserving the overlying skin surface under general anesthesia [Figure 2]. The wound was sutured with 3-0 ethilon and dressing was done. Patient was advised for antibiotic therapy and follow-up after 1 week. Postoperative findings revealed a hard mass with an irregular surface, carrying attached portion of the overlying skin.
Microscopic description revealed fibrocollagenous tissue showing a nodular lesion exhibiting nests of basophilic cells with few areas showing ghost-appearing cells. The nuclei were round to oval. Intervening stroma was fibrocollagenous and in areas showing giant cell reaction. Osseous metaplasia was also identified. Focally skin tissue was identified on the surface. No evidence of any cyst formation or malignancy was seen.
| Discussion|| |
Pilomatrixomas are benign skin neoplasms of hair follicle origin. They are one of the most common superficial masses of the head and neck, excised in children. Although the entity has been well studied in the literature, few studies have been undertaken to evaluate the clinical characteristics of head and neck pilomatrixomas, especially in children. In a retrospective chart review, 91 cases of pilomatrixoma were confirmed in 86 patients. The age range was 5 months to 17 years. Median age at the time of excision was 6.0 years. The most common sites of occurrence were the cheek (36%), neck (20%), periorbital region (14%), and scalp (9%). The male to female ratio was 1:1.5. Multiple lesions were found in 8.2% of patients. 
The distribution of these lesions did not correlate with the density of the hair follicles, but it was in accordance with the distribution of intermediate hair, such as those in the hair border. This relationship may have etiologic significance.  Histopathologic examination of the excised tumors revealed variable basophilic hair matrix cells and sheets of non-viable eosinophilic shadow cells. Foci of dystrophic calcification were also seen in the necrotic tumor areas. 
Beta-catenin is a downstream effector in the Wnt signaling pathway, acting as a signal for differentiation and proliferation. Immunohistochemical and molecular analysis of beta-catenin reveals that mutations in CTNNB1, the gene encoding beta-catenin, are present in a wide variety of benign and malignant neoplasms, and pilomatrix carcinomas may arise from their benign counterparts.  Multiple periocular and facial pilomatrixomas can occur in children in the clinical absence of myotonic dystrophy, Gardner's syndrome, and sarcoidosis.  Other diagnoses include sebaceous and dermoid cysts, foreign body reaction, calcification in lymph gland, and fat necrosis. Factors contributing to misdiagnosis include cystic lesions with varying consistency, punctum-like appearance, atypical location, and absence of clinically recognizable calcification. Despite close excision, the recurrence rate is low.  All pilomatrixomas had been treated for solitary tumors with simple surgical excision and closure.
There are no reported adverse outcomes and no tumor recurrences at the surgical sites. These findings support the use of simple surgical excision as the treatment of choice for these tumors.  The importance of three pillars of diagnosis, i.e., history, examination, and investigation, is well established. A clinician shall always correlate the findings with one another before undertaking any treatment. Pilomatrixoma is a cutaneous neoplasm that is one of the most common causes of superficial head and neck masses in children. Although the pre-surgical diagnosis may be difficult in some cases, pilomatrixoma must be kept in the differential of superficial head and neck masses in children.  Pilomatrixoma was an unusual finding in the General Surgery Department. Awareness regarding the inclusion of dermal appendage diseases is very important while establishing the differential diagnosis for chronic, painless head and neck swellings.
| References|| |
|1.||Curran RC, Crocker J. Skin. In: Curran's Atlas of Histopathology. 4 th ed. Harvey Miller Ltd. United Kingdom: Oxford University Press; 2000. p. 255. |
|2.||Yiqun J, Jianfang S. Pilomatrixoma with a bullous appearance. J Cutan Pathol 2004;31:558-60. |
|3.||Reddy SS, Gadre SA, Adegboyega P, Gadre AK. Multiple pilomatrixomas: Case report and literature review. Ear Nose Throat J 2008;87:230-3. |
|4.||Agarwal RP, Handler SD, Matthews MR, Carpentieri D. Pilomatrixoma of the head and neck in children. Otolaryngol Head Neck Surg 2001;125:510-5. |
|5.||Noguchi H, Hayashibara T, Ono T. A statistical study of calcifying epithelioma focusing on the sites of origin. J Dermatol 1995;22:24-7. |
|6.||Gündüz K, Ecel M, Erden E. Multiple pilomatrixomas affecting the eyelid and face. J Pediatr Ophthalmol Strabismus 2008;45:122-4. |
|7.||Lazer AJ, Calonje E, Grayson W, Dei Tos AP, Mihm MC Jr, Redson M, et al. Pilomatrix carcinomas contain mutations in CTNB1, the gene encoding beta-catenin. J Cutan Pathol 2005;32:148-57. |
|8.||Kumaran N, Azmy A, Carachi R, Raine PA, Macfarlane JH, Howatson AG. Pilomatrixoma accuracy of clinical diagnosis. J Pediatr Surg 2006;41:1755-8. |
|9.||Thomas RW, Perkins JA, Ruegemer JL, Munaretto JA. Surgical excision of pilomatrixoma of the head and neck: A retrospective review of 26 cases. Ear Nose Throat J 1999;78:541-8. |
[Figure 1], [Figure 2]