摘要:

Epithelioid cell histiocytoma (ECH) is an unusual and still poorly recognized variant of benign fibrous histiocytoma. Epithelioid cell histiocytoma differs from most benign fibrous histiocytomas in five important ways: the predominance of epithelioid cells, relative lack of secondary elements (such as giant cells, foamy, or hemosiderin-laden macrophages), relative sharp circumscription, prominent vascularity, and centering in the papillary dermis in most cases. A strong resemblance to melanocytic and vascular lesions has been noted, and a recent case was reported with features suggesting endothelial origin. Fifteen new cases of ECH, including one example of the rare deep cellular variant, are presented herein, with emphasis on features mimicking vascular and melanocytic neoplasms. Labeling with endothelial markers, including previously unreported CD-31 labeling, showed abundant vascular staining, which may be challenging to interpret, but which does not indicate an endothelial origin of ECH.

ISSN:0193-1091    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

The morphologic features of trichofolliculoma are variable, reminiscent of the anagen, catagen, and telogen phases of a normal hair follicle in its cycle. We recently described an early, fully developed stage and late stages of trichofolliculoma. Using immunohistochemical examination, we sought to demonstrate hyperplasia of Merkel cells in all three stages of trichofolliculoma. We found this to be the most striking in small lesions of the late stage. The distribution of the Merkel cells in several stages of trichofolliculoma coincided with the known arrangement of normal follicular Merkel cells during the follicular cycle. However, antibodies against neurofilaments failed to detect innervated Merkel cells, in contrast to normal follicular Merkel cells. Antibodies against Ki67 did not reveal proliferative Merkel cells in any of the trichofolliculomas, but for unknown reasons, a distinct cytoplasmic staining of Merkel cell processes sometimes occurred. Nuclear Ki67 was strongly expressed in the nuclei of follicular keratinocytes of the fully developed trichofollicullomas, whereas those at a late stage showed a markedly decreased staining pattern. Our finding of Merkel cells in all trichofolliculomas underlines their classification as hamartomas with follicular differentiation. Hyperplasia of Merkel cells, even in trichofolliculomas at a late stage, as regressing lesions might implicate hitherto unknown regulatory functions of this neuroendocrine cell.

ISSN:0193-1091    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Merkel cell carcinoma is an aggressive cutaneous neoplasm that is often difficult to diagnose because of its histologic and immunohistochemical similarity to metastatic oat cell carcinomas and other cutaneous neoplasms. Our purpose was to determine the utility of immunoperoxidase staining of cytokeratin 20 (CK 20), a newly discovered intermediate filament protein, in Merkel cell carcinomas and other cutaneous tumors. Sixty-one tumors were sectioned and stained with antibodies directed at CK 20. The staining of Merkel cell carcinomas was compared with metastatic oat cell carcinomas, lymphomas, squamous cell carcinomas, basal cell carcinomas, melanomas, metastatic carcinoids, spiradenomas, eccrine carcinomas, adenoidcystic carcinoma, sebaceous carcinomas, hidradenomas, sebaceous epitheliomas, trichoblastomas, mixed tumors, and metastatic adenocarcinomas. Nine of 10 Merkel cell carcinomas stained with antibody to CK 20. Two metastatic carcinomas to the skin were also positive. One hidradenoma and one squamous carcinoma exhibited focal staining, but were otherwise negative. All other tumors were nonstaining. Cytokeratin 20 is a sensitive and specific marker for Merkel cell carcinoma and is helpful in distinguishing between Merkel cell carcinoma and other malignant and benign neoplasms.

ISSN:0193-1091    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Hypergranulotic dyscornification is an appellation proposed to designate a newly recognized distinctive pattern of epidermal maturation that is analogous to other epithelial reaction patterns such as epidermolytic hyperkeratosis, focal acantholytic dyskeratosis, cornoid lamellation, pale-cell acanthosis, and follicular mucinosis. The name "benign hypergranulotic keratosis with dyscornification" is proposed to specify solitary keratoses with digitated epidermal hyperplasia that exhibit this exceptional pattern of cornification. This abnormal type of cornification is characterized by hypergranulosis. A pale-staining basophilic substance is present intercellularly within the upper spinous layer and the hyperplastic granular layer. Overlying the thickened granular layer in foci at tips of epidermal papillations are orthokeratotic mounds of large, dull, eosinophilic staining corneocytes that are sharply demarcated from the thickened granular layer. Basophilic keratohyalin granules are focally retained within these corneocytes. There is overlying compact orthokeratosis that extends across the entire lesion. The compact orthokeratosis is slightly basophilic, and lies below a laminated and basket-weave orthokeratotic stratum corneum. There is a predominantly lymphocytic infiltrate at the base of these neoplasms with some spongiosis. There is parakeratosis focally present in the stratum corneum overlying these individual areas of abnormal cornification. The histopathologic and clinical findings in eight lesions that exhibit hypergranulotic dyscornification, a heretofore undescribed unique pattern of epidermal cornification, are presented.

ISSN:0193-1091    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

There are few studies on the proliferative activity of cells in Kaposi's sarcoma. It remains unclear whether the different progressive histologic stages of Kaposi's sarcoma correlate with the proliferative activity of the tumor. To clarify this issue, we studied the Ki-67 proliferation index in 40 specimens of acquired immune deficiency syndrome-related Kaposi's sarcoma in correlation with the histologic stage of the lesions. The mean proliferation index in our combined material was rather low (8%, range 1-20%) and there was no significant difference among the different stages of the disease. Contrary to a common and probably misleading concept, our results suggest that the histologic progression of the Kaposi's sarcoma is not related to an increase of the proliferative compartment.

ISSN:0193-1091    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

An unusual case of melanosis associated with metastatic malignant melanoma is reported. This was characterized by progressive blue/gray discoloration of the skin of the chest and abdomen in an elderly patient, 1 year after removal of a polypoid malignant melanoma from the right arm. A biopsy of involved skin revealed perivascular aggregates of melanin-laden histiocytes throughout the dermis, the histopathologic hallmark of melanosis. An unusual aspect of the case was the coincidental finding of a tumor embolus within a small dermal vessel, probably a lymphatic. To date, neoplastic melanocytes have been detected in only a small minority of skin biopsies with features of melanosis. This case and a distillation of related information in the literature lead to the conclusion that the essence of melanosis, and the feature that distinguishes this from conventional metastatic melanoma, is the persistent and cumulative dissemination of melanin, via the bloodstream, throughout the body. This in turn leads to progressive pigmentation of all internal organs and the skin. Only continuous access to the circulation by neoplastic melanocytes could explain such a phenomenon. Potential mechanisms by which this could arise are discussed in the context of existing knowledge.

ISSN:0193-1091    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Traditionally, poromas have been classified as eccrine neoplasms, but several recent reports of poroid tumors with sebaceous, follicular, and apocrine differentiation have challenged this idea. In support of alternative differentiation, a case of an "apocrine" poroma is reported in a 19-year-old man with the nevoid basal cell carcinoma syndrome. A papule on the right cheek, thought clinically to be a basal cell carcinoma, was excised. Anastomosing lobules of small uniform basaloid (poroid) cells formed small ductular structures lined by eosinophilic cuticles and extended into the superficial reticular dermis. The neoplasm originated from follicular infundibula and was surrounded by a myxoid stroma. Focally, primitive hair bulb and papillae differentiation was present, and some of the ducts were lined by cells suggesting decapitation secretion. The histologic pattern and the common embryologic origin of the folliculosebaceous-apocrine unit support apocrine differentiation of this tumor. The association with the nevoid basal carcinoma syndrome appears to be unique. This case, in addition, demonstrates overlapping features with the infundibulocystic type of basal cell carcinoma commonly seen in the basal cell nevus syndrome.

ISSN:0193-1091    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

We report a case of basal cell carcinoma with massive ossification in a 66-year-old white man. Ossification in various benign and malignant neoplasms have been reported including basal cell carcinomas, in which ossifications are seen in small foci or peripheral rim of the tumor. However, in our case, massive ossification is seen throughout the tumor, and only small areas of the periphery of the tumor show diagnostic histology. Therefore, this case might have presented a diagnostic difficulty or been misdiagnosed as an osteoma cutis if a smaller incisional or punch biopsy had been performed. The phenomenon of bone formation itself is not specific for any diagnostic entity, and therefore an underlying lesion should be carefully sought in case of secondary ossification.

ISSN:0193-1091    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

A 74-year-old Japanese man developed a reddish, indurated plaque composed of multiple nodules on his right axilla. Histopathologic examination showed a solid tumor that extended from the upper dermis into the subcutis, with both inter- and intracellular lumen formation, cellular arrangement in single files, a fibrotic reaction around the tumor cells, and the presence of mucinous material in the cytoplasm. There was both nuclear and cytoplasmic pleomorphism. Both lysozyme and GCDFP-15 were identified in the tumor cells. Electron microscopic examination showed periluminal condensation of the cytoplasm. Because thorough clinical and laboratory examinations were unremarkable, we regarded this to be a case of primary adenocarcinoma with signet ring cells of the axilla. The neoplasm might have differentiated toward the apocrine sweat glands or the mammary glands. Radiation therapy was effective to some degree. This seems to be the first reported case in which adenocarcinoma with signet ring cells of the skin affected a site other than the eyelids.

ISSN:0193-1091    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Reactive cutaneous angioendotheliomatosis (RCA) is an uncommon benign disease characterized by intravascular proliferation of endothelial cells. The observation of RCA in infants is exceedingly rare. We describe a case of RCA in a 3-month-old infant. The lesions were characterized by six small purpuric papules (1-2 mm in diameter), distributed on the thighs and neck. The general condition of the patient was good, with no lymphadenopathy, systemic involvement, or fever. The histopathologic features of a papule were characterized by the presence of cohesive aggregates of large mononucleated cells protruding into the lumina of dilated vessels and filling some of them completely. Neither an inflammatory infiltrate nor a proliferation of pericytes were present around blood vessels. Intravascular proliferating cells demonstrated positive staining for Ulex europaeus agglutinin 1 (UEA-1) and for Factor VIII-RA and CD34 antigens. The course of the disease was unremarkable with persistence of the lesions for 8 months; no treatment was started.

ISSN:0193-1091    

出版商:OVID    

年代:1999

数据来源: OVID