Malignant hidroacanthoma simplex: a case report

Hidroacanthoma simplex is a benign tumor of the skin originating from or showing differentiation to the sweat glands. It grossly resembles seborrheic keratosis of Bowen's disease and histologically shows intraepidermal focal growth of epithelial cells. Malignant transformation of this tumor is rare. We report a case of pigmented hidroacanthoma with malignant transformation in a 67-year-old woman. There was a 20-year history of a skin lesion on the right thigh, which first appeared as a small verrucous papule, progressed to a dark-brown colored patch, and then to a pigmented plaque. Histologically, the primary tumor was composed of small squamoid cells with marked cellular atypia. Most of the tumor cells were located in the epidermis. Immunohistochemically, the cytoplasm of some tumor cells showed a positive reaction for epithelial membrane antigen, but not for either carcino-embryonic antigen or the S-100 protein.     

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.     

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.     

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.     

Giant irritated seborrheic keratosis mimicking verrucous carcinoma

A case of giant irritated seborrheic keratosis is reported. The tumor showed an unusually gross appearance for seborrheic keratosis; hence, before surgery, it was suspected of being a verrucous carcinoma. However, examination of the whole histologic constitution of the excised tumor warranted the diagnosis of irritated seborrheic keratosis.     

Pigmented seborrheic keratoses of the vulva clinically mimicking a malignant melanoma: a clinical, dermoscopic-pathologic case study

The diagnosis of seborrheic keratosis is, in general, a clinical one, but in some cases, the differential diagnosis between pigmented seborrheic keratosis and malignant melanoma is difficult. Dermoscopy may improve the early diagnosis of vulvar melanoma and thus play a role in the preoperative classification of pigmented lesions at this particular site. We report the first case of a pigmented seborrheic keratosis of the vulva clinically mimicking a malignant melanoma, whose dermoscopic features have been investigated together with their pathologic correlates. Dermoscopically our case shows the absence of comedo-like openings and the presence of the pseudo-network. Dermoscopy is therefore a useful method for the differential diagnosis of pigmented lesions even in the vulva.     

A case of porocarcinoma arising in pigmented hidroacanthoma simplex with multiple lymph node,liver and bone metastases

Porocarcinoma is a rare skin appendage carcinoma that may arise de novo or be associated with pre‐existing poroma and hidroacanthoma simplex (HAS). Here, we report a case of porocarcinoma arising in pigmented HAS, which led to death from multiple lymph node, liver and bone metastases. A 72‐year‐old Japanese man presented with a brown to focal black flat plaque, measuring 17 × 12 mm, on the posterior region of his right thigh. Histopathological study of the tumor revealed that there was intraepidermal proliferation of small‐sized basaloid cells, and it exhibited the ‘Jadassohn phenomenon’, with dendritic melanocytes, and a few ductal structures were observed. Continuing to the intraepidermal nests, the invasive proliferation of large polygonal cells with occasional intracytoplasmic ductal structures was observed. Carcinoembryonic antigen and epithelial membrane antigen were expressed in some carcinoma cells and they highlighted the intracytoplasmic ductal structures. Multiple lymph node, liver and bone metastases were observed, and the patient died 8 months after the initial surgery. Clinical diagnosis of HAS is extremely rare. Porocarcinoma may be associated with pre‐existing HAS and sometimes shows aggressive behavior. Therefore, pigmented HAS must be included in the differential diagnosis of brown or black lesions. Ishida M, Hotta M, Kushima R, Okabe H. A case of porocarcinoma arising in pigmented hidroacanthoma simplex with multiple lymph node, liver and bone metastases.     

Melanoacanthoma (author's transl)]

A 87-year-old Caucasian women had a recurrent pigmented tumor on the back. Histologically, the lesion was interpreted as being a melanoacanthoma. It was characterized by a proliferation of unpigmented basaaloid cells with aggregates of large prickle cells, forming small horn pearls; furthermore the tumor contained numerous large dendritic cells with large amounts of melanin granules. A short review of the literature is followed by the discussion of the relationship between melanoacanthoma and irritated seborrheic keratosis.     

Regressing seborrheic keratosis - clinically and dermoscopically mimicking a regressing melanoma

The diagnosis of seborrheic keratosis is a clinical diagnosis. In a certain percentage of cases, differential diagnosis between seborrheic keratosis and malignant melanoma is difficult. We describe a case of regressing seborrheic keratosis simulating malignant melanoma. Clinical, dermoscopic and histopathologic examinations were performed for the occurrence of an asymmetric, irregularly demarcated, irregularly pigmented lesion measuring 1.3 x 1.5 cm on the right part of the abdomen in a 76-year-old male Caucasian. In order not to miss melanoma, the excision and histopathologic examination of the lesion with peppering is essential.     

单纯性汗腺棘皮瘤五例皮肤镜特征及文献复习

目的：报道5例单纯性汗腺棘皮瘤（HS）病例,归纳皮肤镜特征,并复习相关文献。方法：检索国内外报道的具有详细皮肤镜资料的HS病例,分析HS的皮肤镜表现。结果：共分析24例患者,包括文献检索到的19例患者和本文报道的5例。24例患者中包括10例无色素型HS和14例色素型HS。无色素型HS的常见皮肤镜表现为多形性血管（100%）,其中肾小球样血管100%,另外较有特征性的花蕊状血管、枫叶状血管及乳红色小球/结构的阳性率分别为20%、10%及40%。色素型HS的常见皮肤镜表现为纤细的黑点/小球（50%）。结论：无色素型HS与色素型HS都有比较特征性的皮肤镜表现。     

Trichilemmal tumor arising in a seborrheic keratosis: analysis of cell kinetics by BrdU staining.

We report a case of a 74-year-old male with a trichilemmal tumor arising in a seborrheic keratosis on the buttock and the results of a cell kinetic study of this tumor using a BrdU staining method. The incidence of trichilemmal tumor arising in a seborrheic keratosis seems to be extremely rare. The labeling index of this tumor was 12.0%; this was a level intermediate between normal epidermis and a variety of hyperproliferative skin diseases such as squamous cell carcinoma, Bowen's disease, and psoriasis vulgaris. DNA replicating cells were present in the germinative layers in normal epidermis and the benign hyperproliferative skin diseases, psoriasis vulgaris. In contrast, DNA replicating cells were found throughout the entire epidermis in premalignant and malignant tumors such as in Bowen's disease and squamous cell carcinoma. In this case, DNA replicating cells were localized mainly in the basal and parabasal cell layers, but also seen in the upper squamous layers. These findings suggest that this trichilemmal tumor had a malignant tendency, though it was slow-growing and relatively benign in nature.     

Melanocytes express 3G5 surface antigen

The 3G5-reactive ganglioside antigen (3G5 antigen) is expressed on the surface of various cell types including pericytes, pancreatic islet cells, thyroid follicular cells, and cells of the pituitary and the adrenal medulla. Expression on melanocytes has not yet been reported. We examined 148 5-microm cryosections of 12 normal skin samples and 45 skin tumors (21 melanocytic nevi, 8 malignant melanoma primaries, 4 metastases of malignant melanoma, 3 basal cell carcinomas, and 9 pigmented seborrheic keratoses) by triple fluorescence technique with the monoclonal antibody 3G5, DNA fluorochrome, and the anti-melanocytic antibody A103 (Anti-Melan-A). In normal skin, 3G5 reactivity was detected in epidermal melanocytes of 4 of 12 cases with 14.8 +/- 24.1% positive melanocytes; 20 of 21 nevi (72.2 +/- 29.1% positive nevus cells, mean +/- SD), 8 of 8 primary melanomas (83.9 +/- 12.3% positive melanoma cells), and 4 of 4 melanoma metastases (82.5 +/- 6.5% positive melanoma cells) expressed the 3G5 antigen. All tumor cells of investigated basal cell carcinoma or seborrheic keratosis were 3G5 negative. This is the first report of 3G5 antigen expression in melanocytes. The data demonstrate high expression of this ganglioside in the aggregated melanocytes of malignant or benign tumors but low or absent expression in singular melanocytes (normal epidermis, seborrheic keratoses) reflecting a different biologic state.     

Pigmented hidroacanthoma simplex with porocarcinoma

A case of pigmented hidroacanthoma simplex showing malignant transformation into porocarcinoma is reported. Although no intracellular duct formation could be observed as in benign tumors, ultrastructurally the tumor cells showed characteristics similar to those of eccrine poroma. Many melanocytes were seen dispersed within the tumoral nests. The melanocyte-keratinocyte relationship was found similar to that occurring in melanoacanthoma. Porocarcinoma cells showed ultrastructural features similar to those of benign cells.     

Benign pigmented tumor with combined features of seborrheic keratosis and compound nevus

A thirty-six-year-old woman with an unusual benign pigmented tumor of the ankle is presented. Histopathology of the tumor showed combined features of a seborrheic keratosis and a compound nevus. Combined pigmented tumors should be included in the differential diagnosis of pigmented lesions.     

Melanoma and seborrheic keratosis differentiation using texture features

Purpose: To explore texture features in two-dimensional images to differentiate seborrheic keratosis from melanoma.
Methods: A systematic approach to consistent classification of skin tumors is described. Texture features, based on the second-order histogram, were used to identify the features or a combination of features that could consistently differentiate a malignant skin tumor (melanoma) from a benign one (seborrheic keratosis). Two hundred and seventy-one skin tumor images were separated into training and test sets for accuracy and consistency. Automatic induction was applied to generate classification rules. Data analysis and modeling tools were used to gain further insight into the feature space.
Result and Conclusions: In all, 85–90% of seborrheic keratosis images were correctly differentiated from the malignant skin tumors. The features correlation_average, correlation_range, texture_energy_average and texture_energy_range were found to be the most important features in differentiating seborrheic keratosis from melanoma. Over-all, the seborrheic keratosis images were better identified by the texture features than the melanoma images.     

Seborrheic keratosis with pseudorosettes and adamantinoid seborrheic keratosis: two new histopathologic variants

Aims:  Seborrheic keratoses are the most common benign cutaneous neoplasms in adult and middle-age patients. There are six distinctive histopathologic variants of seborrheic keratosis, namely, acanthotic or solid, reticulated or adenoid, hyperkeratotic or papillomatous, clonal or nested, irritated and inflamed.
Methods:  We report two additional histopathologic variants of seborrheic keratosis.
Results:  One lesion showed abundant intercellular mucin, closely resembling to adamantinoma, and therefore was named adamantinoid seborrheic keratosis. The other one exhibited a peculiar distribution of the basaloid keratinocytes, which were arranged radially around small central spaces, resulting in pseudorosette formation.
Discussion:  To our knowledge, these two histopathologic variants of seborrheic keratosis have been not previously described in the literature.     

Differences in the Known Cellular Composition of Benign Pigmented Skin Lesions Reflected in Computer-Aided Image Analysis

Background

Computer-aided image analysis (CAIA) has been suggested as an effective diagnostic tool for pigmented skin lesions (PSLs), especially melanoma. However, few studies on benign PSLs have been reported.

Objective

The purpose of this study was to evaluate benign PSLs with our CAIA software and analyze the differences between the parameters of those lesions.

Methods

By using homegrown CAIA software, we analyzed 3 kinds of PSLs-nevus, lentigo, and seborrheic keratosis. The group of seborrheic keratosis was divided into pigmented seborrheic keratosis, sebolentigine, and hyperkeratotic seborrheic keratosis. The CAIA was used to extract the color, as well as the morphological, textural, and topological features from each image.

Results

In line with clinical observations, the objective parameters indicated that nevus was dark and round, lentigo was small and bright, and seborrheic keratosis was large and spiky. The surface of nevus showed the highest contrast and correlation. In topological analysis, the concentricity clearly separated melanocytic lesions from seborrheic keratosis. The parameters of pigmented seborrheic keratosis were between those of typical nevus and seborrheic keratosis.

Conclusion

We confirmed that definite correlations exist between the subjective differentiation by experts'' examination and the objective evaluation by using CAIA. We also found that the morphological differences observed in CAIA were greatly influenced by the composition ratios of keratinocytes and melanocytes, which are already known histopathological characteristics of each PSL.     

Clear-cell porocarcinoma in situ: a cytologic variant of porocarcinoma in situ.

Poromas are benign neoplasms composed of poroid and cuticular cells. Four histopathologic variants of poromas are accepted, according to the architectural features of the neoplasm: hidroacanthoma simplex or intraepidermal poroma; eccrine poroma, which is a poroma connected to the epidermis that extends to superficial dermis; dermal duct tumor, which develops when the neoplasm is composed of small, solid aggregations of poroid and cuticular cells confined to the dermis with little or no connection with the epidermis; and poroid hidradenoma, which is a solid-cystic, dermal poroma. The malignant counterpart of hidroacanthoma simplex is named malignant hidroacanthoma simplex or porocarcinoma in situ. This report describes an example of clear-cell malignant hidroacanthoma simplex, a cytologic variant of porocarcinoma in situ, which, to our knowledge, has not been previously reported. In contrast with other clear-cell neoplasms, a relation with diabetes mellitus could not be clearly established in this case.     

Seborrheic Keratosis: An Acantholytic Variant

Two elderly women with seborrheic keratoses on the abdomen are reported on because of the peculiar histologic appearance characterized by prominent acantholysis. Although the basic histologic architecture was a papillomatous acanthoma corresponding to that of seborrheic keratosis, the upper portion of the lesions showed extensive acantholytic changes and dyskeratotic cells. Differentiation from seborrheic keratosis with focal acantholytic dyskeratosis, warty dyskeratoma, keratosis senilis and acantholytic squamous cell carcinoma could be made on the basis of clinical as well as histological features. Although the histogenesis is uncertain, it seems logical to propose that this is a rare variant of irritated seborrheic keratosis.     

A Possible Case of Eccrine Poroma Arising in Seborrheic Keratosis with Partial Intermediate Malignancy and Tumor of the Follicular Infundibulum

An eighty-year-old woman presented with a eccrine poroma that appeared to have arisen in a seborrheic keratosis lesion on the right side of her abdomen. The tumor consisted of a brownish, flat, elevated lesion with an eroded nodule at its periphery. Histopathological analysis of the flat, elevated lesion revealed benign basaloid and squamoid cells that showed acanthotic upward proliferation, suggesting a seborrheic keratosis. The eroded nodule showed irregular proliferation of slight atypical squamoid cells with, in parts, ductal structures in the upper dermis, suggesting that it was an eccrine poroma with partial intermediate malignancy. In addition to the eroded nodule, an occult tumor clinically accompanied the seborrheic keratosis. Histopathology of the occult tumor revealed fenestrated columns and cords of pale epithelial cells attached to the base of the seborrheic keratosis lesion, which was diagnosed as a tumor of the follicular infundibulum. Although reports of seborrheic keratosis transforming into a sweat gland tumor are rare, the present case suggests that seborrheic keratosis may develop into benign or malignant adnexal tumors, including sweat gland and follicular tumors. Thus, seborrheic keratosis should be considered as a possible precursor of adnexal tumor.