Case report
A 24-year-old Chinese man visited our clinic in March 2008 with a firm nodule that he had had on the left shoulder for 4 months. It had been growing gradually and had been covered with a bulla for 3 months. The contained fluid of the bulla had been removed 2 months ago, but quickly relapsed. There was no history of particular local trauma or chronic irritation at the site of the lesion. Skin examination revealed a cross-shaped, translucent, thick-walled, giant bulla measuring 10 cm × 5 cm on the left shoulder. The underlying nodule had a demarcated borderline with the size of about 2.5 cm. It was protuberant and hard (Fig. 1). Laboratory studies, including blood cell count, urinalysis and serum biochemistry, were all within normal limits. No other significant findings were observed.
The nodule was surgically removed under local anaesthesia. When the bulla was opened at the beginning of the resection, a large amount of serohemorrhagic liquid was secreted from the cut surface of the bulla. The resected nodule had a rough surface (Fig. 2). It was elastic, hard and the content of the nodule was pultaceous. Pathological examination showed that the tumour was composed of irregularly shaped islands of epithelial cells consisting of two cell types: basophilic cells and eosinophilic shadow cells (Fig. 3). Upon total sectioning of the excised lesion, we observed neither cellular atypia nor abnormal mitotic figures. These findings were consistent with a diagnosis of pilomatricoma. There were no recurrences after 6 months of follow-up.Discussion
Pilomatricoma, also known as calcifying epithelioma of Malherbe, is the most common adnexal tumour in children and young adults. Our case was also a young adult. It typically occurs on the head, neck or upper limb. The tumour may show a wide variety of signs [1–4] and may be subcutaneous, ulcerating, perforating, pigmented (with haemosiderin), keratotic, vascular, anetodermic, bullous or telangiectatic and resembling basal cell carcinoma [1, 5, 6]. Bullous pilomatricoma is an uncommon lesion, and only a few cases of this variant exist in the literature [1, 7, 8]. The bullous appearance was attributable to lymphatic obstruction that resulted in the dilation of lymphatic vessels. In the literature the accompanied bulla most frequently had round or oval shape and the size varied from 0.5 to 5 cm [1, 5, 9–12]. However, the pilomatricoma we reported had the unusual feature of a cross-shaped, giant bulla measuring 10 cm × 5 cm overlying the tumour. To our knowledge, it was the largest bullous pilomatricoma in the literature.
Considering the healing of the wound, we excavated the nodule by fenestration operation without excising the covered skin. The bulla disappeared and did not relapse. Consequently, the histopathological examination showed a dermal tumour consisting of irregular aggregations of basophilic cells at the periphery of islands of ghost cells, and did not reveal the extraordinary dilation of lymphatic vessels in the overlying dermis.
Authors declare no conflict of interest.References
1. Julian CG, Bowers PW. A clinical review of 209 pilomatricoma. J Am Acad Dermatol 1998; 39: 191-5.
2. Piel S, Denisjuk N, Schadendorf D, Dissemond J. Giant pilomatricoma: a benign tumor in an uncommon presentation. J Pediatr 2009; 154: 623.
3. Garrido-Ríos AA, Nájera-Botello L, Villanueva AC, Meseguer-Yebra C, Romero-Maté A, Martínez-Sánchez D, Borbujo-Martínez J. Floppy tumor on the shoulder. Int J Dermatol 2011; 50: 921-2.
4. Malpathak VD, Zawar VP, Chuh AA, Ghadi PS. Giant pilomatricoma (pilomatrixoma) following an intramuscular injection. J Dermatol Case Rep 2008; 2: 11-3.
5. Prasad HR, Verma KK, Khaitan BK, Singh MK. Bullous pilomatricoma: a rare occurrence. Acta Derm Venereol 2001; 81: 217-8.
6. Aquilina S, Gatt P, Boffa MJ. Pilomatricoma arising at a BCG vaccination site. Clin Exp Dermatol 2006; 31: 296-7.
7. 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.
8. de Giorgi V, Alfaioli B, Massi D, Gori A, Sestini S, Papi F, Grazzini M, Lotti T. Bullous pilomatricoma: a particular and rare dermal bullous disorder. Acta Derm Venereol 2009; 89: 189-90.
9. Inui S, Kanda R, Hata S. Pilomatricoma with a bullous appearance. J Dermatol 1997; 24: 57-9.
10. Weichert GE, Bush KL, Crawford RI. Bullous pilomatricoma: a report of clinical and pathologic findings and review of dermal bullous disorders. J Cutan Med Surg 2001; 5: 394-6.
11. Fetil E, Soyal MC, Menderes A, Lebe B, Güneş AT, Ozkan S. Bullous appearance of pilomatricoma. Dermatol Surg 2003; 29: 1066-7.
12. Yiqun J, Jianfang S. Pilomatricoma with a bullous appearance. J Cutan Pathol 2004; 31: 558-60.
Address for correspondence
Liming Wu MD
Department of Dermatology
Hangzhou First People’s Hospital
No. 261 Huan Sha Road,
Hangzhou 310006 China
tel. +86 571 8706 5701,
fax +86 571 8791 4773
e-mail: limingwucn@yeah.net
Submitted: 30.06.2012
Accepted: 27.11.2012
