A poroid neoplasia arising close to a seborrheic keratosis and a trichoepithelioma.

A 69-year-old woman had a well-defined, slightly raised, brownish, keratotic plaque with an eccentric group of roughly circular, bluish, dome nodules on her right scapular area. Histological study revealed the presence of an eccrine poroma demonstrating features of eccrine poroma, hidroacanthoma simplex, and dermal duct tumor and arising in a lesion of seborrheic keratosis and a trichoepithelioma. In the eccrine poroma region, an area with malignant changes was evident. The findings in this case support the view of eccrine poroma as a spectrum of histological variants and the possibility of malignant transformation from a eccrine poroma towards porocarcinoma. The association with seborrheic keratosis is most probably coincidental, and the trichoepithelioma was probably due to induction of the tumoral stroma on adjacent follicular epithelia.     

Distribution of epithelial membrane antigen in eccrine poroma.

Using immunohistochemical methods, we investigated the distribution of epithelial membrane antigen (EMA) on the normal eccrine gland, eccrine poroma and hidroacanthoma simplex. Granular membrane-associated reaction of EMA was detected on the outer cells of both the intraepidermal and the upper portion of intradermal eccrine ducts, as well as on the luminal surfaces and intercellular canaliculi of eccrine glands. Clear immunolabeling was also present in the tumor cells of eccrine poroma and hidroacanthoma simplex. Thus, it is suggested that the constituent cells of these tumors originate from the outer cells of the intraepidermal and/or the upper portion of the intradermal eccrine ducts. There was no immunolabeling for EMA on the tumor cells of seborrheic keratosis and basal cell carcinoma. Immunohistochemical staining for EMA is a useful tool for the diagnosis of skin appendage tumors.     

Intra-epidermal and intra-dermal sebocrine adenoma with cystic degeneration and hemorrhage

BACKGROUND: The ducts of eccrine glands may give rise to intra-epidermal, confluent epithelial and intra-dermal adenomas known as hidroacanthoma simplex, eccrine poroma, and dermal duct tumor, respectively. An apocrine and sebaceous counterpart of the eccrine poroma has been described by several authors as adnexal, poroma-like adenoma with apocrine and sebaceous differentiation or sebocrine adenoma. METHODS: Using clinical history and routine histologic techniques, we describe a new lesion with features similar to sebocrine adenoma but representing the intra-epidermal and intra-dermal counterparts with cystic degeneration and hemorrhage. Briefly, an 84-year-old female presented with a 6 mm dark tan papule on the neck that clinically appeared as an unusual macular seborrheic keratosis with underlying hemorrhage. RESULTS: Histopathological examination showed a benign dermal cystic appendage tumor with pale polygonal cells, occasional non-keratinizing ducts, sebaceous differentiation and central hemorrhage with fibrin deposits. Serial sections did not reveal any epidermal connection. However, epithelioid cells with large nuclei in an intra-epidermal pagetoid pattern were focally seen. CONCLUSION: These findings represent a new cystic, hemorrhagic variant of sebocrine adenoma.     

Dermal duct tumor.

A dermal duct tumor occurred on the left leg of a 66-year-old man. The lesion first occurred as a solitary lobulated tumor of approximately 20 years' duration. This apparently brings the total number of recorded cases to 12. It is believed to be a benign tumor of the intradermal portion of the eccrine sweat duct and is distinctive and diagnostic histologically. The spectrum of benign tumors of the eccrine sweat duct epithelium includes hidroacanthoma simplex or intraepidermal eccrine poroma, eccrine poroma, and dermal duct tumor.     

An immunohistochemical study of cutaneous tumors using an antibody to the breast cyst fluid protein (GCDFP-15)

The antibody against a molecular weight 15,000 protein isolated from the breast cyst fluid (GCDFP-15) was applied to tissue from cutaneous tumors, especially to sweat gland tumors. This protein was purified from the breast cyst fluid; antisera was prepared in rabbits. Ninety six cases of cutaneous tumors were stained by the PAP method. Apocrine hydrocystoma, syringocystadenoma papilliferum, so-called mixed tumor of the skin, extramammary Paget's disease, microcystic adnexal carcinoma, and mucinous carcinoma of the skin were positively stained. Eccrine poroma, eccrine spiradenoma, syringoma, eccrine hydrocystoma, papillary eccrine adenoma, adenoid type of basalioma were negative. These observations indicate that the positively stained tumors have functioning seromucous cells, which are characteristic of apocrine gland cells and eccrine dark cells in the skin.     

A rapidly growing eccrine poroma in a pregnant woman

A variety of tumors develop or exacerbate during pregnancy and it is well known that a noticeable increase of eccrine activity occurs in this period. Eccrine poroma is a benign neoplasm that originates from the eccrine sweat gland. The development of this tumor during pregnancy is extremely infrequent. We report a rare case of rapidly growing eccrine poroma in an unusual location (the nose) in a pregnant woman.     

Trichilemmal Differentiation in Seborrheic Keratosis

An 88-year-old woman who developed a nodule in a lesion of seborrheic keratosis on the frontal scalp was observed. Histopathologically, the nodule was characterized by lobular acanthosis consisting of glycogen rich clear cells and squamoid cells with squamous eddies and melanin blockade melanocytes. Each lobule was covered with an orthokeratotic horny layer which formed wedge-shaped masses in its central area without formation of an intervening granular layer. The clinical course and histopathological findings suggest that the tumor cells in seborrheic keratosis may tend to a new development of trichilemmal differentiation.     

A complex poroma-like adnexal adenoma

Hidroacanthoma simplex, eccrine poroma, and dermal duct tumor are benign adenomas that develop from excretory ducts of eccrine glands and all three are variants of eccrine acrospiroma. To date, counterparts in apocrine or sebaceous glands have not been reported, but in this study we describe an adnexal, poroma-like adenoma that showed apocrine and sebaceous differentiations. Apocrine structures have the same embryonic origin as does the pilosebaceous system; both are derived from the primary epithelial germ. We suggest that the lesion we describe is truly a sebaceous and apocrine poroma. It must be distinguished from an infundibular adenoma whose pattern reproduces that of follicular poroma.     

Myoepithelial differentiation in benign sweat gland tumors

One hundred and two cases of benign sweat gland tumors of the skin were studied for the presence of myoepithelial cells specifically identified by a monoclonal antibody to alpha-smooth muscle actin on paraffin-embedded tissues. The monoclonal antibody gave a positive result in 12 of 12 cases of cylindroma, 14 of 16 cases of spiradenoma, 2 of 2 cases of apocrine tubular adenoma (papillary eccrine adenoma), 5 of 5 cases of apocrine hidrocystoma, 5 of 5 cases of hidradenoma papilliferum, and in 10 of 10 cases of syringocystadenoma papilliferum. Rare myoepithelial cells were detected in only 1 of 10 cases of mixed tumor, apocrine type. There was no immunoreactivity for alpha-smooth muscle actin in eccrine hidrocystoma (2 cases), mixed tumor of eccrine type (2 cases), syringoma (7 cases), hidroacanthoma simplex (1 case), eccrine poroma (14 cases), clear cell hidradenoma (15 cases), and in 1 case of eccrine syringofibroadenoma. Our data support the concept that myoepithelial cells are seen in most sweat gland tumors considered to differentiate toward the secretory coil of the normal sweat gland. In contrast, myoepithelial cells are absent in tumors showing differentiation toward the excretory (ductal) component of the gland.     

Características dermatoscópicas del poroma ecrino

Eccrine poroma is a benign adnexal neoplasm that clinically may mimic malignant skin tumors such as squamous cell carcinoma and amelanotic melanoma. The dermoscopic features of pigmented and nonpigmented eccrine poroma have recently been described. We present 2 cases of eccrine poroma, with their dermoscopic features. The lesions were characterized by multiple red lacunes and a polymorphous vascular pattern in both cases. Dermoscopy can improve the clinical diagnosis of this benign adnexal skin tumor.     

Primary cutaneous ganglioneuroma: anatomico‐clinical study of 4 cases with focus on Merkel cells

Cutaneous ganglioneuromas (CGNs) are exceptional. We aim to describe the anatomico‐clinical profile of primary CGN and report 4 cases. Patients were 2 men and 2 women aged 53 to 76 years, who had flesh‐colored nodules on the back, associated with adjacent keratotic changes, that is, epidermal nevus (1 case) or seborrheic keratosis (3 cases). Histopathology showed ganglion cells within a proliferation of Schwann cells. The epidermis was acanthotic, associated with sebaceous induction in 2 cases, with follicular hyperplasia as in fibroepithelial tumors (1 case) or with tricholemmoma (2 cases). Cytokeratin‐20 immunostaining showed Merkel cells in the epidermis. A higher density of Merkel cells was observed in BerEP4+ follicular structures. Along with 16 published cases, our study indicates that a nodule associated with seborrheic keratosis on the back may represent a CGN, a complex mesenchymal and epidermal/follicular lesion of neuroectodermal lineage, associating neuronal proliferation and Merkel cell hyperplasia with follicular induction.     

"Apocrine" poroma: review of the literature and case report

BACKGROUND: "Apocrine" poroma has recently been proposed as a new term to designate a distinctive benign skin neoplasm with differentiation toward the folliculosebaceous-apocrine unit. CASE REPORT: In support of alternative differentiation, a case of apocrine poroma is reported in a 73-year-old man. A nodule on the right upper abdomen, which was thought clinically to be seborrheic keratosis or basal cell epithelioma, was excised. HISTOLOGY: Histologically, this neoplasm heterogeniously consisted of poroma-like, sebaceous and follicular epithelial components. Since these components share the common embryologic origin of the folliculosebaceous-apocrine unit, this histologic pattern indicates apocrine differentiation of the tumor. CONCLUSION: This is an additional case to support the term "apocrine" poroma as a diagnosis.     

Genetic changes in sweat gland carcinomas

The molecular pathogenesis of malignant appendageal tumors is poorly understood. Immunohistochemical staining, polymerase chain reaction (PCR)-based loss of heterozygosity (LOH) and sequencing analyses were performed in a mixed group of 21 sweat gland carcinomas. LOH was mostly confined to the chromosome arm 17p. None of the remaining 17 tumors showed LOH at any loci. Nuclear accumulation of p53 protein was observed in 3 tumors, all of which also showed LOH of 17p. One eccrine gland adenocarcinoma showed allelic loss of 17p and a Cys 176 Arg mutation in the p53 gene. The other three tumors that showed LOH of 17p, however, had wild-type p53 genes. A clear transition from benign eccrine poroma to porocarcinoma that was associated with p53 protein stabilization and allelic loss was observed in one tumor. One eccrine porocarcinoma/undifferentiated adnexal carcinoma showed prominent microsatellite instability, probably reflecting an underlying defect in DNA mismatch repair. Overexpression of erbB-2 was observed in three tumors. The low frequencies of LOH and p53 alterations in sweat gland carcinomas contrasted with the multiple genetic defects normally observed in cutaneous squamous cell carcinomas, and may be partly explained by the relative protection of cutaneous appendages from ultraviolet light and other environmental mutagens.     

Two Cases of Basal Cell Carcinoma Arising in Seborrheic Keratosis

The present study reports two cases of basal cell carcinoma arising in seborrheic keratosis. The first case is a seventy-three-year-old female who presented with a blackish nodule arising from a pigmented lesion on her chest. Histopathological analysis of the nodule and the pigmented lesion revealed a basal cell carcinoma with hair follicular differentiation and an acanthotic seborrheic keratosis, respectively. The second case is a seventy-year-old female with a blackish nodule arising from a pigmented lesion on her back. Histological analysis of the nodule revealed an atypical basaloid cell mass surrounded by a seborrheic keratosis lesion. In addition to the coexisting seborrheic keratosis with the basal cell carcinoma, a basaloid follicular hamartoma that showed muliple hamartomatous hair follicles or small cysts replaced by a branching cord or lace-like network of basaloid cells surrounded by fibrovascular stroma was identified. We concluded that both cases presented a rare combination of a seborrheic keratosis which underwent a malignant change to basal cell carcinoma. It appears that both basal cell carcinomas and seborrheic keratosis may derive from a similar source: pluripotential cells of either the epidermis or hair follicle epithelium.     

Ber-EP4 is a useful marker for follicular germinative cell differentiation of cutaneous epithelial neoplasms

Ber-EP4 is a monoclonal antibody that recognizes 34-kDa and 39-kDa non-covalently linked glycopolypeptides expressed by most human epithelial cells and carcinomas. In this study, we performed immunohistochemical staining of 31 cases of basal cell carcinoma (BCC); 20 cases of trichoblastoma (TB), including ten cases of nodular type, eight cases of cribriform type (trichoepithelioma) and two cases of columnar type (desmoplastic trichoepithelioma); 16 cases of actinic keratosis (AK); and 10 cases each of Bowen's disease, poroma and seborrheic keratosis. Six cases of BCC and AK were co-lesions of both neoplasms. In normal skin tissue, Ber-EP4 reacted positively with the secretory portion of eccrine glands and follicular germinative cells at the lower end of catagen hairs. Neoplastic cells in 97% of cases with BCC reacted positively with Ber-EP4 in at least 5% of neoplastic cells. Those in 90% with nodular type TB and 50% with trichoepithelioma also reacted positively in at least 5% of neoplastic cells. No cases of poroma, seborrheic keratosis, AK or Bowen's disease were immunohistochemically positive for Ber-EP4 in neoplastic cells. In all six cases with co-lesions of BCC and AK, neoplastic cells of BCC reacted positively with Ber-EP4 and those of AK were negative. Immunohistochemical examination using the Ber-EP4 antibody is a useful tool for diagnosing neoplasms with follicular germinative differentiation, such as TB, TE or BCC, and for differentiating those from squamous cell carcinoma in situ, poroma or seborrheic keratosis.     

Poroma: a review of eccrine,apocrine, and malignant forms

Poroma is a benign adnexal neoplasm of the terminal sweat gland duct. Although poromas have traditionally been thought to originate from the eccrine sweat gland, there have been cases of apocrine etiology as well. Eccrine and apocrine poromas typically present as erythematous or flesh‐colored nodules on the palms and soles. As these features overlap with a multitude of differential diagnoses, it is imperative to have a firm understanding of the characteristics that make the diagnosis of poroma. In addition, the malignant counterpart to the poroma, the eccrine porocarcinoma, manifests in a similar nonspecific fashion. Case studies and literature reviews have contributed immensely to our present knowledge of poroma and porocarcinoma. Given the rarity of these neoplasms, however, there remains a relative paucity of information on atypical presentations and rates of malignant transformation. In this article, the epidemiology, clinical presentation, diagnosis, and management of poroma and porocarcinoma will be reviewed. This systematic approach may serve as a guide in navigating the diagnostic dilemma of these rare cutaneous lesions.     

Ekkrines Porom

A 42-year-old man presented with a rapidly growing nodule on his right cheek. Except for some itching, it was asymptomatic. The tumor was excised with 3–4 mm safety margin. The clinical differential diagnostic considerations included pyogenic granuloma, amelanotic melanoma, basal cell carcinoma and eccrine poroma. An eccrine poroma is a rare tumor derived from the eccrine sweat gland. Hormonal disturbances, trauma, immunosuppression, actinic damages and radiotherapy have been suggested as possible etiologic factors; however, the exact pathophysiology remains unclear.     

A Single Lesion Demonstrating Features of Eccrine Poroma and Poroid Hidradenoma

A case of a single poroma lesion with the features of eccrine poroma and poroid hidradenoma is reported. The patient was a 61-year-old woman with a soft nodule, light brown in color, located on the posterior aspect of the right knee and containing a pigmented papular lesion in its center. The histological features of the papular lesion and the nodule were consistent with those of eccrine poroma and poroid hidradenoma, respectively. The eccrine poroma portion consisted mostly of poroid cells. The number of cuticular cells was slightly greater than that of poroid cells in the poroid hidradenoma portion. The cuticular cells in this portion as well as the poroid cells in both portions were immunohistochemically positive for epithelial membrane antigen. The findings in this case suggest that there is a close relationship between eccrine poroma and poroid hidradenoma and support the view that poroid hidradenoma is a type of poroma.     

Unknown: Pedunculated nodule on the foot. Eccrine poroma

Eccrine poroma is a benign adnexal neoplasm composed of epithelial cells with poroid or distal ductal differentiation. We report a healthy 57-year-old woman with a 4-year history of an asymptomatic pedunculated nodule on the lateral border of the right foot that was proven to be an eccrine poroma by histopathologic examination.     

Composite Tumor Associating Trichoblastoma and Seborrheic Keratosis

Seborrheic keratosis is a common benign epidermal tumor histologically composed of basaloid and squamous cells. It mainly occurs on the face, scalp, and trunk, and presents clinically as a well-circumscribed, brownish to black papule, nodule, or plaque. Trichoblastoma is a relatively rare benign, slow-growing tumor showing differentiation toward the primitive hair follicle. It clinically manifests as a solitary, skin to erythematous colored, well-circumscribed dermal nodule located predominantly on the head and neck with a predilection for the scalp. Histologically, a well-demarcated mass of follicular germinative cells that show various degrees of differentiation, arranged in lobules, sheets, and nests, is located in the dermis or subcutaneous fat layer. We report the case of a 28-year-old female patient with a solitary, 2.0×4.0-cm black plaque with a 0.7-cm skin-colored nodule on the scalp. Histologically, the entire black plaque had prominent hyperkeratosis, acanthosis, and papillomatosis with horn cysts. The central nodule showed well-circumscribed, various-sized dermal tumor lobules without a connection to the overlying epidermis. The lobular aggregation was composed of numerous basaloid epithelial nests and multiple primitive papillary structures with distinct peripheral palisading of nuclei. According to these findings, the scalp lesion was diagnosed as a composite tumor associating trichoblastoma and seborrheic keratosis.