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Multiple eccrine spiradenomas are rare. In the present study, a detailed investigation of eccrine spiradenoma was performed, focusing in particular on the presence of Langerhans cells (LCs) in the tumor, and their immunohistochemical and ultrastructural characterization. The patient was a woman in her mid-forties who underwent resection of two tumors of the head that were 2.0 and 0.7 cm in size. They were diagnosed as eccrine spiradenoma and were composed of small and large tumor cells with a dense fibrous capsule in the dermis. Immunohistochemically, staining by antibodies to cytokeratins (AE1/AE3, CAM5.2) and CK 5/6 was diffusely positive in all tumor cells, although not in intermingled LCs, which harbored interdigitated nuclei. The cytoplasm of LCs was positive for S-100 protein and CD1a, and their nuclei were also occasionally positive for S-100 protein. Antibody to epithelial membrane antigen was positive for the surface of both intracytoplasmic and true glandular lumina. Fine structural examination revealed the presence of LCs among the tumor cells, extending fine irregular processes among the tumor cells. Birbeck granules were clearly demonstrated in the cytoplasm of LCs. Other fine structural findings included intracytoplasmic lumina with microvilli on their surfaces in some tumor cells. In these examinations of eccrine spiradenoma, LCs, approximately 15/HPF in the tumor, were distinctly detected even at light microscopic level as negative for various types of cytokeratin stains, although they were positive for S-100 protein and CD1a, whereas on ultrastructural examination Birbeck granules were demonstrated in their cytoplasm. Determination of the significance of these LCs in eccrine spiradenoma requires further investigation of a larger number of cases.

Background: Nodular hidradenoma is a distinctive sweat gland neoplasm. In addition to the well-known histological and cytological features, we hereby describe for the first time nuclear grooving as a useful morphological feature to aid in its diagnosis., Methods: All cases were analyzed for anatomic location, size, age, sex and histology, with attention focused mainly on the nuclear features. A semiquantitative method was used to estimate the percentage of nuclear grooves in five consecutive high-power fields (x40), with confirmation on x100. Electron microscopy was also performed to confirm light microscopic observation., Results: Totally, 34 cases of nodular hidradenoma were studied. All the tumors showed two types of cells. One type of cell contained clear cytoplasm with small, round nuclei. The second type of cell, which was the predominant type, had elongated nuclei. In 30 (88%) of the 34 cases, about 30% of these cells at x40 and x100 magnification showed nuclear grooving. Electron microscopy on these samples confirmed nuclear grooves., Conclusions: In this study, we reviewed 34 cases of nodular hidradenoma. In addition to the classical features, both histologically and cytologically, we describe for the first time the nuclear grooves as a frequent finding in these neoplasms. This finding was also confirmed by electron microscopy. We believe that this newly described histological feature will aid the practicing pathologist to make this important diagnosis.

This report describes the 12th documented case of histiocytoid, diffuse or signet-ring cell eccrine sweat gland carcinoma of the eyelid, a rare neoplasm that characteristically affects older men and mimics distant metastasis. Clinically, the patient was thought to have a colonic metastasis. Histologically, the neoplasm comprised sheets and cords of polygonal, eosinophilic cells, with dispersed larger, rounded single cells resembling histiocytes, and cells with cytoplasmic lumina or a signet-ring appearance. Occasional duct formation was also seen. The features were reminiscent of both the histiocytoid and lobular variants of breast carcinoma. Ultrastructurally, the presence of nonintestinal type microvilli with a length : width ratio in excess of 16 were consistent with an eccrine origin, but also raised the possibility of metastatic mesothelioma. However, a metastatic lesion was excluded by clinical and imaging investigations. There has been no recurrence 3 years after primary excision.

A cutaneous mass at the base of the retroauricular region of a 4-year-old, female Golden Retriever was examined pathologically. Histologically, the mass formed multiple nodules consisting of a proliferation of large clear cells with abundant cytoplasm. Mitotic figures among the neoplastic cells were very sparse. The large clear cells were intensely positive for cytokeratins (AE1/AE4, cytokeratin 8 and 18) and moderately positive for lysozyme and contained periodic acid-Schiff-positive granules in the cytoplasm. In addition, small flat cells lined the islands of neoplastic large clear cells, and these were strongly positive for alpha-smooth muscle actin and vimentin, and some were positive for cytokeratin (AE1/AE4), suggesting they were myoepithelial cells. No local recurrence or metastasis has been recognized during the 18 months since surgical excision. On the basis of these findings, the present tumor was diagnosed as apocrine sweat gland adenoma, clear cell variant. There have been few previous reports of canine apocrine adenomas showing a clear cell morphology.

Background: Syringocystadenoma papilliferum is a benign hamartomatous tumour of the skin. The histogenesis of this tumour is still controversial. There have been few reports regarding immunohistochemical investigations using only a limited range of antibodies and ultrastructural studies on this rare tumour., Objectives: To elucidate the immunohistochemical and ultrastructural properties of this tumour., Methods: We investigated the immunohistological patterns of 12 different anticytokeratin (CK) antibodies and several other markers in five cases of this tumour, comparing them with the patterns in adult sweat glands. One of these cases was also evaluated ultrastructurally., Results: The luminal columnar cells of the tumour were mostly positive for CK7 and more than 70% were positive for CK19. These cells showed the heterogeneous expression of CK1/5/10/14, CK14 and CK5/8. These patterns were also observed in the luminal cells in the secretory or the ductal portion of the adult sweat glands. The basal cuboidal cells of the tumour almost constantly expressed CK1/5/10/14, CK5/8, CK14 and CK7 (except for one case), similar to the patterns of basal cells in the transitional portion and myoepithelial cells in the sweat glands. However, the basal tumour cells expressed CK19 and vimentin heterogeneously, and alpha-smooth muscle actin focally (three cases). Ultrastructurally, the constituent epithelial cells were mainly divided into three types: luminal cells, basal cells and clear cells. The luminal tumour cells bore features of the secretory or ductal luminal cells of sweat glands, although they were somewhat immature in appearance. The basal tumour cells were fundamentally basaloid in nature. The clear cells were undifferentiated or primitive in appearance, suggesting stem or progenitor cell properties. Transitional forms between the clear cells and the other two cell types were also identified., Conclusions: The tumour epithelium was composed of several cell types demonstrating various developmental stages from the primitive clear cells to the basal cells demonstrating a tendency to differentiate toward basal cells in the apocrine transitional portion or myoepithelial lineage, or luminal cells toward the ductal or secretory epithelium. These results support the classical concept that syringocystadenoma papilliferum is a hamartomatous tumour that arises from pluripotent cells.

The ultrastructural morphology of a ceruminous gland adenoma in the middle ear was examined electron microscopically. The epithelial tumor cells displayed apocrine caps, microvilli, cell junctions, secretory granules, vacuoles, lipid droplets and siderosomes, which are the characteristic ultrastructural features of apocrine glands. Concentric membranous bodies of the endoplasmic reticulum, phagocytic activity of the tumor cells, intracytoplasmic lumina, ciliated cells and also spiny collagen in the tumor stroma could be seen. The myoepithelial cells are an important tumor marker in the differential diagnosis between ceruminomas and adenomas of the middle ear. The ectopic origin in the modified apocrine ceruminous glands, the specific localization, the clinical features and the extremely rare occurrence of the ceruminoma makes this tumor a unique neoplastic entity., (Copyright 2002 S. Karger AG, Basel)

Hyaline cell-rich chondroid syringoma (HCRCS) is a rare benign cutaneous neoplasm composed of cells with eosinophilic hyaline cytoplasm and plasmacytoid features, the origin of which remains elusive. To the best of our knowledge, only eight cases of this entity have been reported so far, and none of them was submitted to a large panel of myoepithelial markers. We report on a case of a previously healthy 29-year-old male patient who presented with a slowly enlarging flesh-colored nodule on the palmar aspect of the tenar region of his left hand, measuring 2 cm in maximum diameter. The nodule was "shelled-out" and submitted to light microscopy, immunohistochemistry, and ultrastructural examination. Histopathologic analysis disclosed a lobulated neoplasm composed of hyaline cells with plasmacytoid features showing ovoid nuclei, with occasional invaginations, finely granular chromatin, and discrete nucleoli; the cytoplasm was deeply eosinophilic with occasional dot-shaped paranuclear hyaline inclusions. On immunohistochemical evaluation, hyaline cells were strongly and diffusely positive for S-100 protein, vimentin, pan (CAM 5.2) and high molecular weight (34betaE12) cytokeratins; these cells were focally positive for GFAP, maspin, neuron-specific enolase, and cytokeratin 14. Alpha-smooth muscle actin, epithelial membrane antigen, carcinoembryonic antigen, collagen IV, Gp100 (HMB-45), and p63 were negative in neoplastic hyaline cells. Ultrastructural analysis disclosed cells with ovoid nuclei showing occasional invaginations and nuclear pockets; the cytoplasm was rich in meshworks of non-bundling intermediate filaments and a variable amount of rough endoplasmic reticulum cisternae. Based on our findings and those previously reported, hyaline cells of HCRCS might posses an aberrant myoepithelial differentiation. Most importantly, pathologists need to be aware of the histologic and immunohistochemical features of HCRCS to avoid a misdiagnosis of highly malignant neoplams, such as malignant melanoma and extra-skeletal myxoid chondrosarcoma.

An apocrine adenocarcinoma was observed in the subcutis of the abdomen of golden hamster. Histologically, the tumor cells irregularly formed multiple layers of cysts and some detached cells were presented in the cystic space. PAS stain with alpha-amylase digestion revealed PAS-positive alpha-amylase-resistant granules in the cytoplasm. Immunohistochemically, cytokeratin was demonstrated in the tumor cells. By electron microscopy, the tumor cells had an oval nucleus with invagination, abundant cytoplasmic organelles and microvilli protruding into the intercellular spaces.

Malignant chondroid syringoma, or mixed tumor of the skin, salivary gland type, is an uncommon neoplasm believed to originate in sweat glands. This neoplasm occurs mostly in women and is typically seen in the extremities and torso. A case of recurrent malignant chondroid syringoma of the right foot in a man aged 34 years is described with a review of pertinent literature. The surgically excised neoplasm was evaluated by routine histology, immunohistochemistry, and transmission electron microscopy. The malignant chondroid syringoma showed microscopic dermal satellite tumor nodules. Immunohistochemical staining was positive for keratin and S100 and negative for actin and p53. Ki-67 showed <10% positive staining. Ultrastructurally, the neoplasm was composed of epithelial cells with tonofilaments, cell junctions, and electron-dense amorphous keratin-like substance in the intercellular spaces. No evidence of myoepithelial differentiation was noted. Given the tumoral size, acral location, and histologic findings, the neoplasm was classified as a malignant chondroid syringoma. After reviewing the literature, it became apparent that wide surgical excision, adjuvant radiation therapy as well as patient education are critical in facilitating long-term survival.

Syringoid carcinoma (syringoid "eccrine" carcinoma or eccrine epithelioma) is a rare cutaneous tumor with some controversy regarding its correct definition. It may also be difficult to differentiate from its benign counterpart (syringoma), other adnexal carcinomas, and cutaneous metastasis from adenocarcinomas. We present a case of a syringoid carcinoma of the clear cell variant complemented with an immunohistochemical and ultrastructural study, the latter revealing cytoplasmic accumulation of glycogen and presence of intercellular and intracellular lumina in clear tumor cells, as well as diverse hallmarks of malignancy (i.e., perineural invasion, tumor necrosis, and deep invasion). Clear tumor cells showed cytoplasmic and membranous immunoreactivity to epithelial membrane antigen, carcinoembryonic antigen, keratins, and S-100. Our ultrastructural and immunohistochemical results support the ductal differentiation of the glycogen-filled clear cell tumor population.

Primary mucinous carcinoma of skin is a rare adnexal tumor arising from the eccrine sweat gland. The tumors grow slowly and have low rates of local recurrence and rare chances of distant metastasis. The authors report a 70-year-old man with primary mucinous skin carcinoma who had a relapse in bone marrow 19 months after initial treatment.

Background: Fine needle aspiration cytology (FNAC) can be used for establishing a diagnosis of cutaneous lesions, especially in cases with cyst formation. Poroid hidradenoma is eccrine neoplasm with both solid and cystic components., Case: A 77-year-old female presented with a slightly elevated nodule in the skin on her left elbow. The tumor was well demarcated, 2.7 x 2.4 cm and soft, and overlying skin was slightly reddish. FNAC revealed two types of cell: one had abundant cytoplasm in which small to large, occasionally multinucleated nuclei with small but distinct nucleoli were evident. Chromatin was finely granular, and nuclear membrane was thin and almost smooth. Another type of cell had scanty cytoplasm and a round to oval nucleus with small but prominent nucleoli. Histologic diagnosis was poroid hidradenoma., Conclusion: FNAC can be useful for diagnosing intradermal cystic lesions before surgical resection.

A 45-year-old African American man presented with a small, solitary, nonulcerated cutaneous lesion of the right thigh of many years duration, which was excised. Light microscopically, the lesion consisted of an oval, well-circumscribed, intradermal proliferation of tubules, which were often dilated and lined by a double layer of tumor cells with conspicuous intraluminal papillations. Ultrastructurally, there was evidence of both intradermal eccrine duct and eccrine secretory coil differentiation. Although the majority of tumor cells resembled cells of the intradermal eccrine duct, occasional myoepithelial tumor cells and rare tumor cells having secretory granules and resembling dark mucous cells were indicative of eccrine secretory coil differentiation. The positive immunohistochemical staining for S-100 protein, CEA, EMA, and vimentin supported these ultrastructural findings.

Sweat gland carcinomas are rare skin tumors that typically occur in older patients. The spectrum of their clinical and pathologic features is broad, and many different types of sweat gland carcinomas have been described, ranging from fairly indolent to highly aggressive neoplasms. We present two cases of sweat gland carcinoma with a predominant small cell morphology. Both tumors occurred in children. One lesion developed in an 8-year-old girl as an asymptomatic papule on her left forearm, which ultimately was evaluated using biopsy because of rapid growth and change in color. The other lesion occurred on the hand of a 12-year-old boy. Both tumors were pandermal and extended into fat. They were composed of monotonous cuboidal cells with scant cytoplasm that formed tubules and grew in anastomosing cords and trabeculae. The tumor cells were immunoreactive for cytokeratins but not for cytokeratin 20. Ultrastructural analysis (available in one case only) showed that the tumor cells lacked neurosecretory granules. This variant of sweat gland carcinoma needs to be distinguished from other small cell neoplasms of the skin, especially Merkel cell carcinoma, its closest mimic.

Three cases of cutaneous mixed tumor with atypical features are described. These biphasic tumors comprise cords and nests of often plasmacytoid cells with areas of tubule formation, set in a chondroid stroma. The tumor cells show immunohistochemical positivity for both CAM 5.2 and S-100 and ultrastructural features of myoepithelium. The atypical histological features of an infiltrative margin, satellite tumor nodules, and tumor necrosis, which were present in these cases, have been described in malignant chondroid syringoma; however, a review of the small number of previous case reports demonstrates that histological appearances did not always correspond with apparent malignant potential in this tumor. The term atypical mixed tumor is recommended for tumors in which there are histological features of malignancy, especially local invasion, without proven metastases. Complete excision of the tumor and careful follow-up are advised, as at present the malignant potential of these tumors cannot be reliably predicted from their histological appearance.

Malignant eccrine spiradenoma is an exceedingly rare tumor. A case of a 72-year-old women with this highly aggressive malignancy arising from a long-standing lower leg lesion is reported. Management during the course of disease included surgery, radiation therapy (RT), hyperthermic limb perfusion chemotherapy, and chemotherapy. The patient died of her disease, with widespread metastatic disease 20 months after the diagnosis. A review of the literature is presented, and treatment considerations are summarized.

Aims: The histological, immunohistochemical and electron microscopic features of a primary adenomyoepithelioma of skin, a rare sweat gland tumour, are reported., Methods and Results: The tumour occurred on the back of a 92-year-old woman. It was composed of well-formed tubules lined by epithelial cells surrounded by clear or spindled myoepithelial cells. Immunohistochemically, the epithelial cells exhibited strong cytokeratin (CAM5.2) and weak carcinoembryonic antigen positivity. The myoepithelial cells showed diffuse positivity for smooth muscle actin and focal positivity for S100 protein. Ultrastructurally, the myoepithelial cells contained myofilaments with focal densities and hemidesmosomes. They were limited by well-formed basal lamina. The tumour was associated with a small eccrine spiradenoma., Conclusion: We predict that the tumour will behave in a benign fashion. There is no evidence of recurrence or metastasis 28 months later.

A case of a 60 year old man with malignant eccrine spiradenoma involving the perineum is described. Areas of typical eccrine spiradenoma were admixed with carcinomatous and sarcomatous elements. Immunohistochemical and ultrastructural analysis revealed no evidence of epithelial differentiation in the sarcomatous areas. The tumour qualified for the designation carcinosarcoma arising in eccrine spiradenoma. The clinical course was aggressive with rapid development of nodal and pulmonary metastases.

A 13-year-old male Shetland Sheepdog with progressive exophthalmos had a neoplastic mass in the ocular adnexa. Histologically, this neoplasm was composed of duct-forming epithelial cells with decapitation secretion. Tumor cells invaded the globe through the tunica conjunctiva and replaced the vitreous body. The cornea, iris, ciliary body, and retina were extensively destroyed. Both the epithelial and spindle-shaped myoepithelial cells showed nuclear atypia and mitotic activity in the globe. The primary tumor was diagnosed as adenocarcinoma, probably originating from apocrine sweat glands of the eyelid, and the infiltrating intraocular neoplasm was diagnosed as a malignant mixed tumor.

A 91-year-old man presented with a 9.0 x 7.0 cm exophytic mass on the dorsum of the right foot, surrounded by a scaling hyperkeratotic plaque-like lesion that had been present for many years. He had similar long-standing hyperkeratotic plaque-like lesions on both legs. Histopathologic examination of the exophytic mass revealed a well-differentiated squamous cell carcinoma surrounded by an eccrine syringofibroadenoma (ESFA). Histochemistry, immunohistochemistry and electron microscopy support this diagnosis. To our knowledge, this is the only reported case of ESFA being intimately associated with a malignant neoplasm.

Glycoproteins of the carcinoembryonic antigen family (CEA) and epithelial membrane antigen (EMA) are established markers for glandular and mucosal tissues. However, their precise ultrastructural distribution in sweat glands has not been determined as yet. Therefore, normal human skin, 19 cases of various sweat gland neoplasms, Paget's disease, and cutaneous metastases of visceral carcinomas were stained with well-defined antibodies using a postembedding immunogold technique. In some cases, a new method of re-embedding paraffin material for immunoelectron microscopy was applied. In normal sweat glands, immunoreactivity of the endoplasmic reticulum and vesicles indicated biosynthesis and processing of CEA and EMA. Along the luminal surfaces both CEA and EMA represented an integral part of microvilli. However, a differential expression of CEA and EMA was demonstrated in apocrine epithelia, mucous cells of eccrine glands, and sweat ducts. In fetal glands, CEA was associated with formation of secretory and ductal lumina. The overall cellular distribution of CEA and EMA was highly preserved in benign sweat gland neoplasms whereas malignant neoplasms were characterized by loss of protein targeting and cellular polarity. In conclusion, these immunoelectron microscopical findings suggest a role of CEA and EMA for cell differentiation and secretory mechanisms of sweat gland epithelia.

A case of nodular hidradenoma presenting on the forearm of a 36 year old woman is reported. The diagnosis was made on fine-needle aspiration biopsy (FNAB). The cytologic features of the lesion are described. This is the first case to be diagnosed cytologically.

Acrospiromas are cutaneous tumors of sweat duct differentiation. They usually present as slowly enlarging 1 to 2 cm nodules in middle-aged or older adults without site predilection. On histologic examination they are multilobular dermal masses composed of a biphasic cell population. Acrospiromas are benign, and treatment consists of surgical excision.

Eccrine syringofibroadenoma is a rare benign skin tumor, which usually develops on the extremities of elderly persons. We performed immunohistochemical and ultrastructural studies of a typical case of eccrine syringofibroadenoma that developed on the left heel of a 58-year-old man. The tumor consisted of anastomosing thin epithelial strands connected to the epidermis. There were many ductal or cystic structures, and their luminal cells were strongly positive to antibodies against carcinoembryonic antigen and epithelial membrane antigen. Filagrin and involucrin immunoreactivities were also detected in some cells surrounding the ducts. Keratins K1 and K10, co-expressed in the peripheral cells of normal acrosyringia, were colocalized in small cell clusters. Ultrastructurally, intracellular duct formation characteristic of developing acrosyringia was observed. Tumor cells containing globular keratohyaline granules with various electron densities were seen around some ductal structures. In these areas, keratinization took place without lamellar granule formation or prominent cornified cell envelope assembly. These results suggest acrosyringial differentiation of this tumor.

We report a 49-year-old woman with an eccrine syringofibroadenoma. An asymptomatic nodule appeared on the right heel, and subsequently enlarged gradually. Histological examination revealed anastomosing strands of pale epithelial cells, with occasional duct formation and mucinous fibrovascular stroma. There were two types of strands: thick and thin. Immunohistochemical study, using a panel of monoclonal antikeratin antibodies, revealed that the immunoreactivity differed between the two types of strands. The thick strands showed a staining pattern similar to the uppermost portion of the intradermal duct, and the thin strands showed a pattern similar to the other portion of the duct. This observation suggests that the thick and thin strands differentiate towards the uppermost portion and the remainder of the duct, respectively.

A 73-year-old woman with a malignant hidroacanthoma simplex on her right lower limb is reported. The lesion was immunohistochemically studied. Carcino-embryonic antigen and epithelial membrane antigen were found in the luminal border of ductal structures within the aggregations of neoplastic cells. We review the literature on this subject.

We report a case of a tumor arising in the preauricular region in a 50-year-old woman. The histopathological findings revealed it to be a ductal sweat gland carcinoma connected to a syringocystadenoma papilliferum (SCAP) arising in a nevus sebaceus. Mucinous stroma, considered to be deposition of hyaluronic acid, was also observed in the ductal carcinoma portion. The immunohistochemical and ultrastructural findings in the ductal carcinoma were compared with those in the SCAP. The proliferating cell nuclear antigen labeling index of the cells in the ductal carcinoma was higher than that of those in the SCAP. Both the ductal sweat gland carcinoma and SCAP showed findings compatible with the ductal segment of a sweat gland.

A representative case of hidroacanthoma simplex was studied with routine light microscopy, immunohistochemistry, and electron microscopy. Staining with the periodic acid-Schiff reagent and immunostaining with anti-keratin antibodies were useful in demarcating the tumor cells from adjacent normal epithelium. However, antibodies to carcinoembryonic antigen and epithelial membrane antigen did not help us to segregate or identify the neoplastic cells. Electron microscopy revealed tumor cells markedly different in appearance from luminal cells of the acrosyringium. Hidroacanthoma simplex does not appear to be derived from luminal cells of the acrosyringium. We propose criteria for the histologic diagnosis of this benign neoplasm.

A case of axillary sweat gland carcinoma which metastasised to both lungs six years after resection of the primary lesion is described. The lesions were resected and three years later two further pulmonary metastases were resected.

A single poroid neoplasm composed of three histologically distinct lesions (hidroacanthomas simplex, eccrine poroma, and dermal duct tumor) is reported. Comparative histologic, histochemical, and electron-microscopic studies revealed that each tumor subtype contained varying proportions of poroid cells, clear cells, and cuticular cells. The major component of all three neoplasms was poroid cells, which, under the electron microscope, were characterized by a few, small, poorly developed desmosomes, and were histochemically characterized by a positive succinic dehydrogenase reaction. The dermal duct tumor was cultured, and showed similar histochemical findings to the in vivo poroid cells. These results suggest that poroid cells play the most important role in the histogenesis of these three neoplasms.

The luminal cell layer of acrosyringia contains heterogeneous globular keratohyalin granules, some of which contain basophilic and eosinophilic components. Using immunoelectron microscopy we found that the majority of the granules, which are basophilic, are strongly reactive to an anti-filaggrin antibody, while the minority, which are eosinophilic, are not. Similar heterogeneous keratohyalin granules were observed in syringomas and in an eccrine syringofibroadenoma. Since such granules are not normally observed in other human cutaneous epithelia, it is suggested that these composite keratohyalin granules with partial filaggrin immunoreactivity might serve as a useful marker for acrosyringial differentiation in both normal and pathological material.

Fine needle aspiration cytology of one case each of chondroid syringoma and syringocystadenoma papilliferum with histopathologic confirmation are reported. The aspirate of chondroid syringoma was characterized by the presence of two distinct components, a mesenchymal element with a chondroid appearance and an epithelial component. The chondroid element predominated in the smears. The aspirate from syringocystadenoma papilliferum showed papillalike clusters and dyshesive, monomorphic epithelial cells in a background of inflammatory cells. The clinical diagnosis and differential cytodiagnoses are discussed.

The apocrine nevus (AN) is a rare tumor occurring in the upper chest and the axilla. We report a case of a AN in a 33-year-old female occurring unilaterally. The presenting complaint related to tenderness and swelling in the right axilla. The initial impression was hidradenitis suppurativa. The gross specimen revealed the presence of irregular thickening just beneath the dermal subcutaneous interface. Microscopically the lesion was composed of mature apocrine glands with apical snouts. The glands were arranged in lobules divided by thin fibrous septa. Immunohistochemical studies revealed the following profile in the glandular epithelium: positive low molecular weight cytokeratin, epithelial membrane antigen, and gross cystic disease fluid protein reactivity and negative high molecular cytokeratin and S-100 protein reactivity. Carcinoembryonic antigen reactivity was found in the duct epithelium. Ultrastructural studies revealed cells lining the lumen of the glands with a concentration of granules in the apical region and light and dark granules. These findings support the previously described light microscopic observations and provide unreported ultrastructural studies in this rare tumor.

Four cases of microglandular adenosis (MA), together with four cases of apocrine adenosis (AA) and 10 cases of tubular carcinoma (TC) of the breast were studied at the light and immunohistochemical level. One case of MA was studied with electron microscopy. MA is characterized by an absence of myoepithelial cells (ME), epithelial membrane antigen (EMA), and gross cystic disease fluid protein (GCDFP-15). The absence of EMA in MA makes it unique among benign glandular hyperplasias of the breast. AA contains myoepithelial cells and a distinct basal lamina. It is characterized by the presence of GCDFP-15, the specific apocrine marker, which is not present in MA. TC lacks both myoepithelial cells and a basal lamina. It is negative for GCDFP-15. Periductal and vascular elastosis are common and usually prominent, whereas they are not found in either MA and AA. Other stromal changes further distinguish the three lesions. These three distinct entities can be separated objectively and unequivocally and it is essential that this be done so as to prevent confusion.

Background: Apocrine carcinomas of the skin are rare and incompletely studied neoplasms., Methods: An immunohistochemical and ultrastructural study is reported of specimens from six patients with apocrine skin carcinoma in various body sites. Three tumors were in the axilla; one, the eyelid; one, the ear; and one, the scalp. There were three local recurrences and three regional lymph node metastases, but no patient died of cancer (follow-up, 2-10 years)., Results: The most reliable histopathologic criteria for identifying apocrine skin carcinoma appear to be decapitation secretion, periodic acid-Schiff-positive diastase-resistant material in the cells or lumen, and immunoreactivity with gross cystic disease fluid protein 15. All specimens expressed common epithelial antigens (cytokeratins, carcinoembryonic antigen, and epithelial membrane antigen) and histiocytic-secretive antigens (Leu-M1, lysozyme, LN5, alpha-1-antitrypsin, and alpha-1-antichymotrypsin). S-100 protein was found in the three nonaxillary tumors. Ultrastructurally, the primary tumors, and especially the secondary lesions, were dedifferentiated compared with normal apocrine glands., Conclusions: Apocrine differentiation in skin tumors does not indicate an exclusive origin from the apocrine sweat glands; these neoplasms usually have an indolent clinical course.

We report a rare case of mucinous carcinoma of the skin with mammary infiltrating carcinoma-like patterns. An 82-year-old Japanese male had a gourd-shaped tumor on his scalp. Histopathologically, the posterior portion of the tumor showed small lobules of cuboidal tumor cells with no atypia floating in mucinous lakes. In the anterior portion, there were solid lobules, cords, and strands of anaplastic tumor cells infiltrating into the surrounding stroma. Enzyme- and immunohistochemistry and electron microscopy confirmed the eccrine origin of this tumor. It is suggested that mucinous carcinoma of the skin can occur in association with diverse histological patterns, analogous to mucinous carcinoma of the breast.

To confirm the eccrine acrosyringeal differentiation of eccrine syringofibroadenoma (ESFA) and to elucidate the histogenesis of its angiofibrotic stroma, a case of ESFA from a 45-year-old man was examined by light and electron microscopy. Histologically, the parenchyma featured anastomosing, slender epithelial cords containing small cuboidal cells and occasional duct-like structures. The stroma had increased numbers of mast cells, increased capillaries with swollen endothelial cells, and prominent fibrosis. Ultrastructurally, the following findings were characteristic of ESFA: a) abundant glycogen particles in epithelial cells, b) numerous intracytoplasmic and extracellular spaces lined with microvilli, c) intraepithelial duct formation, consisting of microvilli, vesicles, rod-shaped dense bodies, multivesicular dense bodies, and peripheral network of tonofilaments, and d) large numbers of mast cells, closely associated with fibroblasts, surrounding increased numbers of capillaries containing swollen endothelial cells. These ultrastructural features support the acrosyringeal differentiation of ESFA. We hypothesize that mast cell hyperplasia and degranulation may play an important role in the formation of the angiofibrotic stroma.

We report a case of multiple cylindromas with a linear arrangement on the lower right extremity. The patient had more than 100 tumors, but the scalp was spared. Some tumors showed overlapping features with eccrine spiradenoma. We believe this is the first report of multiple linear cylindromas.

A 56-year-old man had an 11-year history of a psoriasiform eruption of the palms, soles, and shins. An examination revealed well-demarcated patches and plaques of erythematous, fissured, and hyperkeratotic skin with focal erosions. There was no clinical evidence of ectodermal dysplasia. On histologic examination these lesions proved to be eccrine hamartomas that consisted of anastomosing cords and strands of cuboidal epithelial cells with well-formed ducts and a fibrovascular mucinous stroma. Eccrine ductal origin was indicated by histopathologic, histochemical, immunopathologic, and electron microscopic evaluation. These multiple palmoplantar eccrine hamartomas, unassociated with ectodermal dysplasia, represent a sporadic hamartomatous condition that is best designated as "eccrine syringofibroadenomatosis."

Primary eccrine carcinoma and metastatic mammary duct carcinoma are histologically similar and histogenetically related neoplasms that may on occasion be mistaken for one another. Mammary duct carcinomas, in primary or metastatic sites, will often express estrogen and progesterone receptors (ER and PR), and these may be detected by either biochemical or immunocytochemical methods. The expression of ER and PR in primary eccrine carcinoma, however, has not been studied. Three eccrine carcinomas were probed with antibodies to ER and PR. Immunoreactivity for hormone receptors was identified in all three cases. The recognition of this immunophenotype may be important in avoiding misdiagnosing receptor-positive eccrine carcinoma as metastatic breast cancer.

We examined 32 cases (38 lesions) of extramammary Paget's disease (EMPD) in relation to comparative studies on intraductal carcinoma of the breast (ductal carcinoma in situ, DCIS) and apocrine adenocarcinoma (AAC). Lesions included scrotum (18 lesions), vulva (8), axilla (6), groin (3), penis (2) and chest wall (1), and the distribution was compatible with that of apocrine or supernumerary mammary glands. Histologically, extra-mammary Paget's and DCIS cells exhibited a large amount of a pale-stained cytoplasm. The cytoplasm of AAC cells frequently contained granules, was eosinophilic and differed from that of Paget's or DCIS cells. Immunohistochemical studies revealed positive reactions for polyclonal and monoclonal antibodies to carcinoembryonic antigen in all EMPD and most DCIS, but not in AAC. Recent studies have shown that extramammary Paget's cells exhibit characteristics of glandular epithelial cells and that most cases of EMPD are not accompanied by an underlying carcinoma. The results obtained in this study, coupled with data on the frequency of the supernumerary breasts, lead to the speculation that extramammary Paget's cells originate from ectopic mammary glands or from pluripotential germinative cells in the epidermis, capable of differentiating toward the mammary glands.

A case of malignant eccrine tumor and its histological findings were reported. In this case, we considered basal cell carcinoma or malignant melanoma clinically; however, the histological features matched those of malignant eccrine tumor. It has been said that it is very difficult to determine the origin of tumors of sweat apparatus; to contribute to this ongoing dialogue, the classification of tumors of eccrine sweat apparatus was also discussed.

A case of papillary eccrine adenoma was analysed with immunohistochemical and ultrastructural methods regarding their direction of differentiation. It was found that the majority of the structures show either eccrine ductal or glandular differentiation. There were some segments, particularly in those exhibiting papillary growth, where cells similar to eccrine secretory (clear) cells or cells with characteristics of both ductal basal cells and glandular myoepithelial cells were present.

Comprehensive clinical, morphologic, and ultrastructural studies of 12 cases with various forms of carcinoma of the sweat glands permitted distinguishing the clinical nodular and papular-cystic forms. Histologically malignant analogs of benign tumors, primary adenocarcinomas, and unclassified tumors are distinguished. The histogenetic appurtenance of the tumors of the latter group may be identified only by ultrastructural studies that help detect a number of organ specificity signs. Electron microscopy used in the diagnosis of poorly differentiated tumors of the skin helps carry out adequate therapeutic strategy and permitted a better validated prediction.

To investigate biological characteristics of syringomas, three-dimensional (3-D) architectures of epithelial tumor nests and luminal structures of syringomas, hair follicles, and epidermal basement membrane in skin lesions were reconstructed using a computer stereographic analysis. Each lesion was composed of many spherical- to ovoid-shaped tumor nests, which interconnected with each other by narrow tumor strands, showing features of ginger roots or budding fungi. Small discrete tumor nests were often present in the peripheral areas of the lesions. Tumor nests developed around hair follicles and beneath epidermis, but they were never connected with hair follicles or epidermal basement membrane, although occasionally such structures were slightly bent by a pressure from the developing tumor nests. There was no relationship between tumor nests and normal sweat glands. Many tumor nests formed luminal structures; however, some small tumor nests did not. Most of the luminal structures were disconnectedly present. These findings suggest that in each lesion syringoma may occur in a single focus in the upper dermis without a relationship to the surrounding normal epithelial tissues, develop and partly swell forming lumina, and then the peripheral parts of the tumor may become discrete. The ratio of [lumen volume/tumor nest volume] measured by computer stereometry was 0.275 +/- 0.037 (n = 5); this indicates a constant ability to form luminal structures by syringoma cells.

We present four new cases of tubular apocrine adenoma. Clinical histopathological and ultrastructural findings are discussed. The presence of carcinoembryonic antigen (CEA) has been studied in three cases of tubular apocrine adenoma. This antigen was found predominantly in the lumen of the ducts and in the apical portion of the luminal cells. This pattern is similar to the distribution described in normal sweat glands and in other adnexal tumors.

Thirty benign and seven malignant adnexal tumors of the skin and one lymph node metastasis were stained for laminin and type IV collagen with rabbit antibodies against the human basement membrane (BM) proteins using the immunoperoxidase technique. Fifteen of the benign sweat gland, sebaceous gland, and hair follicle tumors showed a continuous and distinct BM around the tumor aggregates. The cylindromas and eccrine spiradenomas seemed to produce excessive amounts of BM material, part of which was seen as amorphic patches within the tumor cell clusters, whereas the trichofolliculomas, trichoepitheliomas, and pilomatrixomas showed an absence of BM from many areas. In syringomas, in addition to the tubular structures surrounded by a continuous BM, undifferentiated cell nests containing granular BM material were present. They probably represent primitive structures obtaining during early development into tubules. The seven malignant tumors and the only metastasis studied here all contained small, narrow strips of BM material extracellularly between the infiltrating tumor clusters. Only in two cases was faint staining for laminin found within the cells. The pepsin pretreatment of the formalin-fixed, paraffin-embedded samples had most probably degraded the intracytoplasmic BM material in most cases. The BM defects were found to be associated with malignancy and low differentiation of the adnexal skin tumors, as reported previously for other tumor types, but a partial loss of BM was also associated with high differentiation in some benign adnexal tumors.