Pilomatricomal horn: a new superficial variant of pilomatricoma

We describe a pilomatricomal horn on the right arm of a 39-year-old man. Although initially the tumor was clinically thought to be a verruca vulgaris, the microscopic features were similar to those found in classic pilomatricoma, except for the epidermal location and the presence of a cutaneous horn. Light microscopy showed replacement of the epidermis by basaloid cells, with masses of cornified material containing shadow cells that formed a cutaneous horn. Whereas classic pilomatricoma is confined to the deep reticular dermis or subcutis, the present case represents a unique heretofore unreported epidermal variant of pilomatricoma that pathologists should be aware of to differentiate it from malignant epidermal tumors.     

Pseudocystic pilomatricoma: A new variant and review of the literature

A classic pilomatricoma, which usually presents with an asymptomatic, solitary, firm, subcutaneous nodule in the head, neck, or extremities of the paediatric population, is easily diagnosed based on its characteristic clinical and histopathological features. However, its variants often pose particular diagnostic challenges to clinicians due to their rarity and diverse clinicopathological features. We present a new pseudocystic variant, manifesting as solid lesions floating in a fluid‐filled sac.     

Giant pilomatricoma

A 52-year-old man was examined for an ulcerated, rapidly growing reddish nodule. It was 5.5 cm high with an 11 x 6-cm base and located on the left clavicle. The lesion had been present for approximately 7 years, and the patient complained occasional burning and pain. Clinical differential diagnoses included cutaneous lymphoma, sarcoma, squamous cell carcinoma, and cutaneous metastasis. Histopathologic examination revealed a well-circumscribed tumor involving the whole dermis and the subcutis and composed of partially confluent aggregates of matrical cells admixed with eosinophilic cornified material containing shadow cells. In addition, multinucleated giant cells, areas of calcification and metaplastic ossification, edema, and hemorrhage were also observed. On the basis of histopathologic features, the diagnosis of pilomatricoma was made. Our report highlights an unusual clinical appearance of pilomatricoma that made us consider a variety of primary or secondary cutaneous neoplasms in its differential diagnosis.     

Perforating pilomatricoma

A case of "perforating pilomatricoma" is reported. A cutaneous horn-like tumor, the size of a grain of rice, developed on the left upper arm of a 51-year-old man. Histological examination revealed typical microscopic features of pilomatricoma. In addition, however, an interesting phenomenon was observed: a small portion of the mass had extruded from the upper dermis to the skin surface through the perforated epidermal channel. It might have been possible in this case for all of the tumor mass to be extruded by transepithelial elimination.     

Malignant pilomatricoma

An 86-year-old man had a tumor in the right posterior cervical region. The lesion showed histopathologic features of pilomatricoma but differed from that lesion by the presence of cytologically atypical cells and focal squamoid differentiation. The term "malignant pilomatricoma" is suggested for this tumor.     

Anetodermic pilomatricoma

A pilomatricoma, or Malherbe's calcifying epithelioma, is an uncommon tumor originating from hair matrix cells. It is clinically characterized by a solitary, firm nodule. As the skin overlying the pilomatricoma may change in color and texture, its clinical presentation can vary. We report an unusual case of pilomatricoma with associated anetoderma on the lower extremity of a 12-year-old girl. Histology revealed a thinned dermis replaced by myxomatous tissue between the surface and a deep-seated tumoral mass. This mass is formed of irregular islands of basaloid cells, shadow cells, calcified areas and discrete inflammatory and foreign-body reactions surrounding it. Anetodermic cutaneous changes may occur in pilomatricomas without histological evidence of triggering factors.     

Proliferating pilomatricoma

We report on 9 patients with pilomatricomas that showed unusual histopathologic features. Our patients were mainly elderly individuals (age range 42 to 88 years; mean age 70.1 years) who presented solitary cutaneous nodules situated on the head and neck (7 neoplasms), upper arm (1 neoplasm), and back (1 neoplasm). All the lesions were treated by simple excision. Follow-up data available in 7 of the 9 patients (mean follow-up, 17 months) revealed local recurrences in 1 patient whose lesion recurred 3 times. No lymph node involvement or distant metastases were recorded in any of our cases. Histopathologically, most neoplasms were characterized by a relatively large lesion in the clermis that in some cases showed extension to the subcutis. Each lesion was predominantly composed of a lobular proliferation of basaloid cells in association with adjacent focal areas containing eosinophilic, cornified material with shadow cells. In some cases, relatively large areas of shadow cells were present, whereas, in others only small foci of shadows cells were observed. Cytomorphologically, the basaloid cells showed features of matrical and supramatrical cells of a normal hair follicle and exhibited variable nuclear atypia and mitotic figures. The overall architectural pattern of the neoplasms was different from that of large fully developed stereotypical pilomatricomas that maintain a cystic character with basaloid cells predominantly aligned at the periphery. Based on the histopathologic findings, namely the presence of a large, lobular proliferation of basaloid cells in association with small to large foci of shadow cells, we interpreted these neoplasms to be a distinctive proliferative variant of pilomatricoma and propose the designation "proliferating pilomatricoma." Proliferating pilomatricomas should be differentiated from the recently described matricoma, basal-cell carcinoma with matrical differentiation, and matrical carcinoma (pilomatrical carcinoma).     

Perforating pilomatricoma

A case of perforating pilomatricoma is described. A few published cases have shared the following features: rapid development, reddish exophytic clinical appearance with surface alterations suggestive of perforation, relatively shallow location making contact with the epidermis, and the occurrence of transepithelial elimination phenomena.     

Lymphangiectatic Variant of Low-Grade Malignant Eccrine Spiradenoma

Low-grade malignant eccrine spiradenoma (spiradenocarcinoma) is a rare sweat gland tumor, which usually arises from a pre-existing benign eccrine spiradenoma. This paper presents the case of a 55-year-old male who had a lesion in his right elbow for 10 years. The microscopic examination revealed a well-demarcated, multilobulated tumor in the dermis and subcutis, which presented with many blood-filled vessels and extensive hemorrhage. The tumor was composed of hyperchromatic, round to oval cells with nucleolar prominence, mild to moderate atypia, and increased mitotic index. Additionally, lymphangiectatic appearance was observed in areas with prominent stromal lymphedema. P53 and Ki-67 had high positivity. Surgical excision of the lesion was performed with adequate surgical margins, and the dissected lymph nodes in the axilla were tumor-negative. After 15 months of follow-up, there was no recurrence or distant metastasis.     

A case of perforating pilomatricoma

Pilomatricoma is a rare skin neoplasm, most commonly seen in the head and neck region, and occurring in the first two decades of life. It is usually solitary and varies from 0.5 to 2 cm in diameter. Its etiology is unknown. Perforating pilomatricoma is a rare clinical variant that presents as a draining, crusted nodule or ulcer, and is reported to arise faster than the classic pilomatricoma. Herein, we report a case of 35-year-old female, who had a 4-month history of a growing mass on her leg. On physical examination, a 4-cm diameter, asymptomatic, erythematous, ulcerated mass was noted on the left anterio-lateral upper leg. The first histopathological analysis of a punch biopsy from the lesion was reported as basal cell carcinoma. Therefore, the lesion was totally excised. There were shadow cells, squamoid cells, and basaloid aggregations more prominently in the one area in the tumor. In addition, calcification, foreign body giant cells and inflammatory cells were present. Punch or excisional biopsies are preferred as a method of diagnosis for the majority of cutaneous neoplasms. If total excision is not the method of choice, multiple punch biopsies should be made from different areas in large skin tumors for correct diagnosis.     

水疱型毛母质瘤一例

正临床资料患儿,女,13岁。因右侧肩部结节5个月,出现水疱样外观1个月,于2015年7月29日就诊。5个月前,患儿右侧肩部出现一蚕豆大小淡红色质硬结节,缓慢增大;1个月前结节表面出现水疱样外观,无自觉症状。自起病以来,患儿无发热、肌无力、肌肉酸痛及肌肉萎缩等全身症状。患儿既往体键,无传染病及遗传病史,家族成员中无类似疾病患者。皮损局部无外伤史或蚊虫叮咬史。体格检查:一般情况可,     

水疱样毛母质瘤一例

患者男,75岁.因颈后部肿物3月余,于2009年11月来我科就诊.就诊前3个月摸到颈后部一绿豆大小硬结,无明显不适,未予处理.此后自觉皮损迅速增大,但无局部与全身不适感.否认发疹前局部有外伤史.既往体键,否认心、肺、肝、肾、脑重要脏器疾病史.家族中无遗传性疾病史及类似疾病患者.