Eccrine angiomatous hamartoma is an uncommon, benign clinical entity constituting a nodular proliferation of eccrine glands and vascular structures localized to the dermis that typically present as unilateral, flesh-colored, erythematous, or violaceous papules on the extremities. These hamartomas may be associated with pain, hyperhidrosis, joint deformity, or functional impairment depending on the severity of the disease process. We present a case of bilaterally symmetric, asymptomatic eccrine angiomatous hamartomas involving all proximal interphalangeal joints of both hands. To date, there are only four prior cases of bilaterally symmetric eccrine angiomatous hamartomas reported in the literature, suggesting that the distribution experienced by our patient may represent a previously undescribed syndrome.

Eccrine nevus (EN) is a very rare hamartoma of the skin and with varying clinical manifestations. Histologically, these neoplasms present as a proliferation of normally structured eccrine sweat glands in the dermis. There have been no more than 20 cases previously have been reported in the English literature. Herein we report a 25-year-old man with eccrine nevus on the neck. To our best knowledge, this is the first case that the lesion affecting the neck.

Fibrous hamartoma of infancy (FHI) is a rare benign soft tissue tumor with a triphasic organoid histologic appearance. The authors present a case of a 21-month-old healthy girl with a slowly growing flesh-colored subcutaneous plaque 12cm in size on the lower back, with overlying hypertrichosis. A punch biopsy revealed a proliferation of spindle cells infiltrating the dermis and hypodermis organized in a dense storiform pattern with a strong diffuse positivity for CD34. The diagnosis of congenital dermatofibrosarcoma protuberans (DFSP) was considered and an excision was performed. Histopathologic analysis showed an extensive poorly demarcated mass infiltrating the dermis and hypodermis, composed of different components: a monomorphous fibroblastic/myofibroblastic component, a mature adipose component, and an immature mesenchymal basophilic component. The clinical aspects with the histologic and immunohistochemical features led to the diagnosis of giant fibrous hamartoma of infancy. In our case the strong diffuse CD34 positivity was a diagnostic pitfall leading to an incorrect hypothesis of congenital DFSP. The characteristic triphasic histology of FHI was missed owing to the small size of the punch biopsy. This article highlights the importance of being aware of the CD34+ dermal mesenchymal tumor differential diagnosis and the necessity of appropriate size biopsies to avoid sampling error.

Angiokeratomas are benign vascular ectasias in the papillary dermis associated with epidermal changes in the form of hyperkeratosis and/or acanthosis. Clinically, angiokeratomas appear as solitary or multiple dark red to purple-black macules and/or papules, mostly with a verrucous surface. Five subtypes of angiokeratoma have been proposed - angiokeratoma corporis diffusum, angiokeratoma of Mibelli, angiokeratoma of Fordyce, angiokeratoma circumscriptum, and "solitary and multiple" angiokeratomas. We report an unusual case of multiple angiokeratomas in a zosteriform distribution with onset at age 74.