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Year : 2017  |  Volume : 18  |  Issue : 4  |  Page : 344-345

Bullous pilomatricoma overlying a Bacillus Calmette–Guérin scar: A rare presentation

1 Department of Dermatology, Lady Hardinge Medical College and Associated Hospitals, New Delhi, India
2 Department of Dermatology, Baba Saheb Ambedkar Hospital, New Delhi, India
3 Department of Dermatology, Tvacha Skin Clinic, Noida, Uttar Pradesh, India

Date of Web Publication29-Sep-2017

Correspondence Address:
Rubina Jassi
Department of Dermatology, Lady Hardinge Medical College and Associated Hospitals, New Delhi
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/2319-7250.206048

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Pilomatricoma is a benign hamartoma of hair matrix and the most commonly occurring hair follicle tumor. It classically presents as skin colored to erythematous, smooth, deep-seated nodule of firm consistency. Rarely, a bullous presentation of a pilomatricoma has also been reported. Herein, we illustrate a case of bullous pilomatricoma occurring over the Bacillus Calmette–Guérin scar site.

Keywords: Bullous, hair matrix tumor, hamartoma, pilomatricoma

How to cite this article:
Ramchander, Yadav P, Pratap P, Jassi R. Bullous pilomatricoma overlying a Bacillus Calmette–Guérin scar: A rare presentation. Indian J Paediatr Dermatol 2017;18:344-5

How to cite this URL:
Ramchander, Yadav P, Pratap P, Jassi R. Bullous pilomatricoma overlying a Bacillus Calmette–Guérin scar: A rare presentation. Indian J Paediatr Dermatol [serial online] 2017 [cited 2021 Jun 24];18:344-5. Available from: https://www.ijpd.in/text.asp?2017/18/4/344/206048

  Introduction Top

Pilomatricoma (benign calcifying epithelioma of Malherbe) is an uncommon, slow-growing benign adnexal skin tumor, which differentiates toward the hair matrix.[1] Up to 75% of pilomatricomas possess activating mutations of the β-catenin gene.[2]

We report a case of bullous pilomatricoma overlying a Bacillus Calmette–Guérin (BCG) scar in a young girl.

  Case Report Top

An 8-year-old girl presented with an asymptomatic single fluid-filled lesion over the left arm which gradually progressed in size over the last 1 year. There was no history of any spontaneous rupture or bloody/fluid discharge from the lesion. There was no history of any low-grade fever, weight loss, and fatigue.

Examination revealed a single 1.5 cm × 1.5 cm bulla overlying a single, hard swelling over the left arm BCG scar site [Figure 1].
Figure 1: (a) Fluid-filled erythematous bullae over the Bacillus Calmette–Guérin scar. (b) Unremarkable epidermis with well-demarcated tumor nodules in dermis (H and E, ×4). (c) Basaloid cells with indistinct cell boundry, scant cytoplasm, and basophilic nuclei (H and E, ×40). (d) H and E section showing shadow cells (ghost cells) with distinct cell boundry and central unstained area

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An excisional biopsy was performed which showed epidermis lined by stratified squamous epithelium, and the dermis showed nests of darkly stained basaloid cells, few giants cells (shadow cells), and anucleated ghost cells with focal areas of calcification at places suggestive of pilomatricoma. There was no recurrence during 1 year follow-up.

  Discussion Top

Pilomatricoma is the most common hair follicle tumor. It is a benign hamartoma of the hair matrix with cells undergoing mummification.[1] It commonly affects females under the age of 20 years. The tumor classically presents as a solitary, deep dermal or subcutaneous tumor of size ranging from 3 to 30 mm over the head, neck, or upper extremities. Pilomatricoma can also rarely presents as uncommon variants such as giant, perforating, ulcerative, multiple erosive, familial, cutaneous horn, and bullous pilomatricoma.

Pilomatricoma was also found to be association with myotonic dystrophy, Gardner's syndrome, Turner's syndrome, and Rubinstein–Taybi syndrome have been reported with pilomatricoma.[1]

In contrast to classical pilomatricoma, bullous pilomatricoma has a predilection of shoulder and upper arm regions in females. The peak age is around 10–20 years and reported mostly of sizes varying from 1 to 3 cm.[1]

Histopathological hallmarks of pilomatricoma are the tumor nests of basophilic cells and eosinophilic shadow cells.

Bullous variant in addition to these findings, shows dilated lymphatic vessels, giant cell reaction, lymphedema, disruption of collagen fibers, dilated blood vessels, fibrous capsule, calcification, nests of transitional cells, and necrosis.[1] Less than 20 cases of bullous pilomatricoma have been reported worldwide with only 3 cases from India. The lesion has also been described resembling the bouncy ball appearance [1] or a stage in transition to secondary anetoderma.[3]

The exact cause of this bullous transformation is not clear. However, theories hypothesize it to be a sequel of mechanical irritation,[4] pseudo blistering,[5] or elastinolytic enzyme production leading to dissolution of the tissue collagen and dilatation of lymphatic vessels.[4],[6]

However, most accepted theory is that the obstruction and congestion of lymphatics forms the bulla.[6],[7]

The lesion in our patient was seen over the BCG scar which could have caused lymphatic obstruction due to scarring and contributed to the formation of bullous lesion. Thus, our case provides further impetus to the lymphatic obstruction theory. However, how the BCG scar could have contributed to the formation of pilomatricoma still remains a mystery to be answered.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Belliappa P, Umashankar N, Raveendra L. Bullous pilomatricoma: A rare variant resembling bouncy ball. Int J Trichology 2013;5:32-4.  Back to cited text no. 1
Chan EF, Gat U, McNiff JM, Fuchs E. A common human skin tumour is caused by activating mutations in beta-catenin. Nat Genet 1999;21:410-3.  Back to cited text no. 2
Bhushan P, Hussain SN. Bullous pilomatricoma: A stage in transition to secondary anetoderma? Indian J Dermatol Venereol Leprol 2012;78:484-7.  Back to cited text no. 3
  [Full text]  
Inui S, Kanda R, Hata S. Pilomatricoma with a bullous appearance. J Dermatol 1997;24:57-9.  Back to cited text no. 4
Yiqun J, Jianfang S. Pilomatricoma with a bullous appearance. J Cutan Pathol 2004;31:558-60.  Back to cited text no. 5
Fetil E, Soyal MC, Menderes A, Lebe B, Günes AT, Ozkan S. Bullous appearance of pilomatricoma. Dermatol Surg 2003;29:1066-7.  Back to cited text no. 6
Chen SY, Wu F, Qian Y, Zhu L, Tu YT, Huang CZ. Pilomatricoma with bullous appearance: A case report and review of literature. Int J Dermatol 2011;50:615-8.  Back to cited text no. 7


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