1/36. Epithelioid cell histiocytoma: a simulant of vascular and melanocytic neoplasms.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.- - - - - - - - - - ranking = 1keywords = dermis (Clic here for more details about this article) |
2/36. Plexiform fibrohistiocytic tumor of the foot.The first case of plexiform fibrohistiocytic tumor in the foot is presented in this article. The tumor developed on the dorsum of the left foot in a 14-year-old female. This tumor was originally described in 1988 by Enzinger and Zhang. Their study indicated that this tumor has a female predominance, median age of 14.5 years, 63% located in the upper extremities, 37.5% recurrence rate, and 3% metastasis rate. These tumors are very unique with a nodular pattern and a cellular component of histiocytes, fibroblasts, and multinucleated giant cells. Typically they are located within the deep dermis and subcutaneous tissue. Immunohistochemical preparations show that the tumor does not stain for S-100 protein, desmin, cytokeratin, factor viii-related protein, or lysozyme. However, it does stain for alpha-1-antitrypsin, alpha-1-antichymotrypsin, alpha-smooth muscle-specific actin, vimentin, and CD68 antibody.- - - - - - - - - - ranking = 1keywords = dermis (Clic here for more details about this article) |
3/36. Generalized eruptive histiocytoma of childhood associated with rheumatic fever.We describe a widespread papular eruption in a 5-year-old girl with rheumatic fever. Histological examination revealed a dense histiocytic infiltration in the dermis. On immunohistochemical studies, the cells were positive for vimentin, CD68, MAC387, alpha1-antichymotrypsin and lysozyme, but negative for CD1a and S-100 protein. Electron microscopic studies showed no Birbeck granules in their cytoplasm. A diagnosis of generalized eruptive histiocytoma of childhood was established. The skin lesions completely disappeared within 8 months.- - - - - - - - - - ranking = 1keywords = dermis (Clic here for more details about this article) |
4/36. Metastasizing fibrous histiocytoma of the skin: a clinicopathologic and immunohistochemical analysis of three cases.The clinicopathologic and immunohistochemical features of three metastasizing fibrous histiocytomas of the skin are presented. The first patient had a 1.3-cm nodule in the right thigh, with right inguinal lymph node metastases 19 years later. The second patient, who had a 3-cm nodule excised from his left thigh and inguinal lymph node metastasis after 4 months, had a favorable outcome 14 years after local radiotherapy and chemotherapy. The third had a 2-cm nodule in his neck, which recurred 16 months later. Four months later, cervical lymph node metastases were found. The patient was alive and well 26 months after initial surgery. All three primary skin tumors involved the dermis and subcutis, appeared well-delineated but nonencapsulated, were associated with some degree of epidermal hyperplasia, and showed features of aneurysmal/atypical or cellular fibrous histiocytoma. The number of mitoses ranged from 6 to 11 per 10 high-power fields. Recurrences and metastases showed morphologic features similar to primary lesions. Tumor cells were positive, at least focally, for CD 68, Ki-M1p, and factor xiiia, and occasionally for smooth muscle actin. desmin, CD 34, S-100 protein, and cytokeratin stainings were negative. Primary neoplasms, recurrences, and metastases showed a Mib-1 labeling index of 10% or less. Cellular, aneurysmal, and atypical (pseudosarcomatous) fibrous histiocytomas of the skin can metastasize, yet they often show a protracted clinical course. risk factors for metastatic dissemination include large size, high cellularity, aneurysmal changes, marked cellular pleomorphism, high mitotic activity, tumor necrosis, and repeated local recurrences.- - - - - - - - - - ranking = 1keywords = dermis (Clic here for more details about this article) |
5/36. Atrophic dermatofibroma. Elastophagocytosis by the tumor cells.A 55-year-old woman presented with an asymptomatic red plaque on the left upper back for 6 or 7 years. The lesion was depressed in response to finger pressure. The clinical diagnosis was anetoderma. Histopathologically, the characteristic cells of cellular dermatofibroma proliferated within the thinned dermis, which showed atrophy of about 60 or 70%. The proliferated cells were positive for factor xiiia and negative for CD34. The involved dermis showed the loss of elastic fibers on elastica van Gieson stain. Electron microscopically, the proliferating cells phagocytized the elastic fibers. We report a typical case of atrophic dermatofibroma and show the possibility that the cause of this disease might be elastophagocytosis between the collagen fibers by the dermatofibroma cells.- - - - - - - - - - ranking = 2keywords = dermis (Clic here for more details about this article) |
6/36. Histiocytic disorders with spontaneous regression in infancy.The histiocytic disorders are uncommon, have a wide spectrum, and are poorly understood. We describe seven cases developing in infancy, seen during a period of 9 years at Asan Medical Center, Seoul, korea. Clinically the patients had multiple papules over the face, trunk, and extremities that developed at birth or during infancy. Histopathologic examinations revealed an infiltrate of many histiocytic cells in the upper dermis with or without epidermotropism. Four cases were classified as congenital self-healing reticulohistiocytosis in that the histiocytes were identified as langerhans cells by positive immunohistochemical staining for S-100 protein, ultrastructural studies showing many Birbeck granules, and spontaneous regression of the lesions within 1-4 months. One infant with a solitary lesion on the forehead was diagnosed as solitary, congenital, indeterminate cell histiocytoma because the histiocytic cells were S-100 protein positive, but meticulous ultrastructural studies did not detect Birbeck granules. The lesion was removed by shave excision. Two cases were classified as generalized eruptive histiocytoma. The histiocytic cells were S-100 protein negative and ultrastructurally Birbeck granules were absent. In one patient, eyeball- or popcornlike lysosomal structures were seen. The lesions regressed completely.- - - - - - - - - - ranking = 1keywords = dermis (Clic here for more details about this article) |
7/36. Sebaceous hyperplasia: a clue to the diagnosis of dermatofibroma.We describe a man with an indurated lesion on his upper back that showed a dermatofibroma with overlying sebaceous hyperplasia. Characteristic dermal features of a dermatofibroma may be sparse or absent in a lesional specimen that has been submitted subsequent to a superficial shave biopsy. hyperplasia of sebaceous glands in a nonfacial lesion is a histologic feature that should prompt the search for a dermatofibroma in the underlying dermis.- - - - - - - - - - ranking = 1keywords = dermis (Clic here for more details about this article) |
8/36. Cutaneous malignant fibrous histiocytoma with the characteristics of different variants.We report the case of a 50-year-old woman with cutaneous malignant fibrous histiocytoma (MFH) on the right hypogastric region. A purplish-red blood-filled tumor, approximately 40 mm in diameter, was detected on the region. A histopathologic analysis of the excised tumor showed that it extended from the upper dermis to the subcutaneous tissue over the fascia and, furthermore, that a variety of cells, from highly atypical spindle shaped to histiocytelike, were embedded in the collagenous stroma without forming a capsule. The storiform pattern was not significant. In addition, an area occupied primarily by multinucleated giant cells and rich in vascular components was observed in the deep portion of the tumor that came into contact with the bloody contents. Based on these findings, the patient was diagnosed as having a cutaneous MFH exhibiting the characteristics of different variants.- - - - - - - - - - ranking = 1keywords = dermis (Clic here for more details about this article) |
9/36. Decreased CD44 expression and stromal hyaluronate accumulation in myxoid dermatofibroma.BACKGROUND: Dermatofibroma (DF) is a common benign histiocytic tumor, which has several clinicopathological variants. Myxoid DF is one of these variants, which is characterized by a stromal mucin deposition. CD44 is a polymorphic transmembrane glycoprotein and the principal cell surface receptor of hyaluronate (HA), the major component of the extracellular matrix. In a recent study, we have observed an abnormal accumulation of HA in the superficial dermis of transgenic mice with a keratinocyte-specific CD44 expression defect. We have also shown that HA was accumulated in large amounts in the superficial dermis of lichen sclerosus et atrophicus (LSA) lesions and that the epidermal CD44 expression of LSA skin was significantly decreased or lost. In an another study, we have suggested that a decrease in CD44 expression in follicular epithelial proliferations might be correlated with an abnormal HA accumulation in perifollicular solitary cutaneous myxoma. Recently we have also demonstrated that classical DF lesions displayed a strong CD44 expression in tumor cells and a weak HA positivity in tumor stroma whereas CD44 expression was significantly reduced or absent in dermatofibrosarcoma lesions and the tumor stroma showed strong HA staining. OBJECTIVE AND methods: Here we present 3 cases of myxoid DF, in which we explored the nature of the mucinous material in myxoid stroma by colloidal iron and hyaluronic acid binding protein stainings, as well as the expression of CD44 in the tumor cells by immunohistochemistry. RESULTS: We show that HA is accumulated in the stroma of all myxoid DF lesions with a significant decrease in CD44 expression in the tumor cells. CONCLUSION: Our results suggest that a decrease in CD44 expression in the tumor cells may result in stromal myxoid changes characterized by an abnormal HA accumulation in myxoid DF.- - - - - - - - - - ranking = 2keywords = dermis (Clic here for more details about this article) |
10/36. Cutaneous myxoid fibroblastoma. A histological, immunohistochemical, and ultrastructural study.A fibroblastic skin tumor with a myxoid matrix is reported that cannot be easily classified as one of the well-known entities of fibrous/fibrohistiocytic and myxoid skin tumors. A 27-year-old white woman presented with a reddish, dome-shaped cutaneous nodule 8 mm in diameter on the left popliteal fossa that had developed spontaneously within the preceding 2 years. There was no sign of recurrence 30 months after excision. light microscopic examination showed a well-circumscribed tumor confined to the upper dermis and consisting of stellate and spindle-shaped cells arranged loosely in a fascicular pattern resembling tissue cultures of fibroblasts. There were almost no collagen bundles between tumor cells, and Mowry's staining showed large amounts of glycosaminoglycans. Immunohistochemical studies of the tumor cells showed reactivity only to vimentin, whereas markers of histiocytes, dermal dendrocytes, and neurogenic and myogenic differentiation were negative. By electron microscopy, the majority of tumor cells contained elliptical nuclei, but some tumor cells had conspicuous multisegmented nuclei with several large and small nuclear segments connected by thin nuclear bridges (labyrinth nuclei). Single fibrils were found within the interstitium; collagen fibers were rare. Histological and ultrastructural examinations identified tumor cells as fibroblasts. High cellularity distinguishes this tumor from cutaneous myxoma. We conclude that this lesion represents a newly recognized tumor of fibroblastic origin. The name cutaneous myxoid fibroblastoma is proposed.- - - - - - - - - - ranking = 1keywords = dermis (Clic here for more details about this article) |
| | Next -> |