Porocarcinoma is a rare, cutaneous adnexal malignancy usually seen in elderly patients. We present three females with varying lesions located at the head region with a history of a sudden increase in growth. Histologically, all were composed of nests of basaloid cells showing atypia, mitotic figures and eccrine-differentiated ductal elements. One patient underwent excision (0.5 cm margin) and was recurrence-free one-month post-op. This series also brings a brief review of the current literature on porocarcinoma.
Eccrine Porocarcinoma

Eccrine porocarcinoma is a rare malignant tumor arising from the intraepidermal ductal portion of the eccrine sweat gland. It develops either spontaneously or from a long standing benign eccrine poroma. This entity usually affects older people and is commonly located on the lower extremities, the trunk, and the head. We report a case of eccrine porocarcinoma on the left cheek in an 85-year-old male. In our case, the tumor was treated with wide excision and postoperative adjuvant radiation therapy. The patient recovered well without local recurrence and distant metastasis during the 14-month follow-up period. Wide excision and postoperative adjuvant radiation therapy can be considered as a safe and effective treatment option in treating patients with eccrine porocarcinoma.
Aged, 80 and over ; Cheek ; Eccrine Porocarcinoma ; Follow-Up Studies ; Head ; Humans ; Lower Extremity ; Male ; Neoplasm Metastasis ; Poroma ; Radiotherapy, Adjuvant ; Recurrence ; Sweat Gland Neoplasms ; Sweat Glands

No abstract available.
Eccrine Porocarcinoma ; Poroma*

A ‘collision’ tumor refers to the existence of two different neoplasms within the same tumor. Sometimes, the term ‘biphasic tumor’ is also used. However, a ‘collision’ tumor is defined as the occurrence of two neoplasms within proximity of each other yet maintaining distinctly defined, separate boundaries. In contrast, a ‘biphasic’ tumor demonstrates two or more phenotypically distinct neoplastic cell populations merging within the same space. Here, we report a case of collision tumor associated with sarcomatoid eccrine porocarcinoma and basal cell carcinoma arising in a 57-year-old male patient.
Carcinoma, Basal Cell* ; Eccrine Porocarcinoma* ; Humans ; Male ; Middle Aged

Eccrine porocarcinoma is a rare malignant neoplasm of the eccrine sweat gland that often occurs in the lower extremities, and usually affects elderly individuals. Most cases of eccrine porocarcinoma arise de novo. We encountered a case of a large porocarcinoma arising in a pre-existing ganglion cyst in the knee. The malignant tumor was excised widely, and the defect was reconstructed using a free anterolateral thigh flap.
Aged ; Eccrine Porocarcinoma ; Ganglion Cysts* ; Humans ; Knee ; Lower Extremity ; Sweat Glands ; Thigh

OBJECTIVETo investigate the clinicopathological features and the differential diagnosis of poroma and porocarcinoma.

METHODSHistopathological characteristics and clinical data of 35 cases of poroma and 10 cases of porocarcinoma were analyzed retrospectively.

RESULTSThe average age of 35 patients of poroma was 48 years. The average age of 10 patients of porocarcinoma was 65 years. Both poroma and porocarcinoma occured most frequently on the scalp and face,as well as the extremities. Histologically, cases of poroma were divided into three subtypes, including classic poroma (23 cases), hidroacanthoma simplex (3 cases) and dermal duct tumor (9 cases). Residual foci of benign poroma were found in all cases of porocarcinoma, most of which were classic poroma. The malignant components showed severe dysplasia and/or stromal infiltration.

CONCLUSIONThe diagnosis of poroma and porocarcinoma is mainly based on the microscopic characteristics. An invasive architectural pattern and/or significant cytologic pleomorphism are the most important clues for the diagnosis of porocarcinoma. Neither focal mitotic activity nor the presence of necrosis was the diagnostic feature of porocarcinoma. Malignant transformation can occur in some cases of long existing poroma with recent, rapid tumor enlargement.

Aged ; Cell Transformation, Neoplastic ; Diagnosis, Differential ; Eccrine Porocarcinoma ; pathology ; Extremities ; Head and Neck Neoplasms ; pathology ; Humans ; Middle Aged ; Poroma ; pathology ; Retrospective Studies ; Scalp ; Skin Neoplasms ; pathology ; Sweat Gland Neoplasms ; pathology

Eccrine porocarcinoma is a rare cutaneous neoplasm arising from the eccrine sweat duct. It may arise de novo or evolve from a pre-existing poroma or hidroacanthoma simplex. The pigmented variant of porocarcinoma is very rare, and its heavy pigmentation can lead to misdiagnosis of seborrheic keratosis or melanoma. An 82-year-old male patient presented with a painful, brown-to-black colored plaque measuring 4x4.5 cm with a central pedunculated nodule that measured 2.5x2 cm on his right posterior thigh. A small, pigmented papule had developed 10 years prior and had gradually increased in size. Histopathologic examination of the nodule revealed lobulated tumor islands composed of atypical basaloid cells in the periphery, eosinophilic squamous cells in the center, and pigmented dendritic cells scattered throughout nests of the tumor. Carcinoembryonic antigen and epithelial membrane antigen were expressed in the tumor cells and the dendritic cells stained positive for S-100 and HMB45. Histopathologic findings from the plaque showed many pigmented nests embedded within the epidermis that were composed of small, polygonal, pigmented basaloid cells. Pigmented eccrine porocarcinoma arising from pigmented hidroacanthoma simplex was diagnosed clinically and histopathologically. The tumor was completely excised. We report a case of pigmented porocarcinoma, which should be included among clinically important differential diagnoses apart from melanoma.
Aged, 80 and over ; Carcinoembryonic Antigen ; Dendritic Cells ; Diagnosis, Differential ; Diagnostic Errors ; Eccrine Porocarcinoma* ; Eosinophils ; Epidermis ; Humans ; Islands ; Keratosis, Seborrheic ; Male ; Melanoma ; Mucin-1 ; Pigmentation ; Poroma ; Sweat ; Thigh

Eccrine porocarcinoma is a rare malignant tumor. Immunostain for S-100 protein, in addition to epithelial membrane antigen (EMA) and carcinoembryonic antigen (CEA), is described to be useful in the diagnosis. Herein, we report a case of eccrine porocarcinoma with immunostain for S-100 protein which was useful in diagnoses of recurrent and metastatic lesions. The primary lesion in the left inguinal region was excised, but it recurred on the same site 14 months after the resection. The recurrent lesion showed epithelioid melanocytic findings. Three months later, metastasis to the lungs was found. Since these recurrent and metastatic lesions were dedifferentiated, typical histologic findings of eccrine porocarcinoma disappeared in biopsied specimens. Nevertheless, scattered immunoreactive cells for S-100 protein were maintained in these dedifferentiated lesions. S-100 protein positive cells could be an aid to diagnose, even if histologic findings of recurrent and metastatic lesions have changed by dedifferentiation.
Carcinoembryonic Antigen ; Eccrine Porocarcinoma ; Immunohistochemistry ; Lung ; Mucin-1 ; Neoplasm Metastasis ; S100 Proteins

Eccrine porocarcinoma is a rare malignant tumor. Immunostain for S-100 protein, in addition to epithelial membrane antigen (EMA) and carcinoembryonic antigen (CEA), is described to be useful in the diagnosis. Herein, we report a case of eccrine porocarcinoma with immunostain for S-100 protein which was useful in diagnoses of recurrent and metastatic lesions. The primary lesion in the left inguinal region was excised, but it recurred on the same site 14 months after the resection. The recurrent lesion showed epithelioid melanocytic findings. Three months later, metastasis to the lungs was found. Since these recurrent and metastatic lesions were dedifferentiated, typical histologic findings of eccrine porocarcinoma disappeared in biopsied specimens. Nevertheless, scattered immunoreactive cells for S-100 protein were maintained in these dedifferentiated lesions. S-100 protein positive cells could be an aid to diagnose, even if histologic findings of recurrent and metastatic lesions have changed by dedifferentiation.
Carcinoembryonic Antigen ; Eccrine Porocarcinoma ; Immunohistochemistry ; Lung ; Mucin-1 ; Neoplasm Metastasis ; S100 Proteins

Eccrine porocarcinoma is a rare, malignant skin tumor that originates from the eccrine sweat gland. This disease affects elderly people, primarily. It is clinically present in varied forms and the location is not related to sweat-gland distribution, which occurs on the lower limb, trunk, and head. Herein, we report a rare case of pedunculated eccrine porocarcinoma, which had developed on the flank of a 79-year-old woman.
Aged ; Eccrine Porocarcinoma ; Female ; Head ; Humans ; Lower Extremity ; Skin ; Sweat Glands