Diffuse dermal angiomatosis

Diffuse dermal angiomatosis (DDA) is an acquired, benign vascular proliferation characterized clinically by poorly circumscribed, violaceous, livedoid plaques with frequent ulceration. Histologically, a diffuse interstitial proliferation of CD31-positive endothelial cells is present within the papillary and reticular dermis. Endothelial atypia, atypical mitoses, and vasculitis are lacking. We describe a case of DDA in a 53-year-old man with peripheral vascular atherosclerosis that resolved following revascularization. Early correction of the associated ischemic peripheral vascular disease promotes resolution of this unusual clinicopathologic entity.     

Cutaneous pseudosarcomatous polyp: a histological and immunohistochemical study

Two unusual acquired polypoid skin lesions exhibited prominent histological atypia, but were biologically benign. Both patients were elderly females. The lesions clinically mimicked fibroepithelial polyp or nevus lipomatosus. Both had been present for about 20 years. One lesion was located on the back, the other on the posterior thigh. Each lesion exhibited dilated, hyalinized vessels in the dermis with focal fibrin deposits, myxoid stroma, and a population of bizarre, pleomorphic spindle to stellate cells, some of which were multinucleated. Occasional atypical mitoses were present. One lesion had abundant admixed fat. Immunohistochemical staining was strongly positive only for vimentin. The lesions share features with degenerating angiofibroma and vaginal pseudosarcomatous polyp. As in these lesions, the atypia is most probably reactive and degenerative.     

Infiltrative glomus tumor arising from a benign glomus tumor: a distinctive immunohistochemical pattern in the infiltrative component

Malignant glomus tumors (MGT) are rare. Although metastatic MGT has been reported, most MGT have only been locally aggressive, some with multiple local recurrences. We report an additional case of an infiltrative glomus tumor. In addition to the pattern of immunohistochemical staining for alpha-smooth muscle actin (SM-actin) previously described, we performed immunohistochemical stains for Ki-67 and CD34. The infiltrative component of the glomus tumor showed variably decreased staining with SM-actin and occasional tumor cells showed nuclear staining with Ki-67. CD34 staining occurred in stromal cells forming the pseudocapsule in the benign component of this tumor and in other benign glomus tumors. The infiltrative component showed increased CD34 stromal cells. Although Ki-67 staining showed only an occasional proliferative cell, the immunohistochemical staining pattern of CD34 and SM-actin raise the possibility that the infiltrative component of this tumor may have differences in the degree of differentiation from the circumscribed part and that local factors could support its spread from a conventional benign glomus tumor.     

High-grade trichoblastic carcinosarcoma

A case of low-grade trichoblastic carcinosarcoma was reported in 2004. Here we present the second case of this tumor, which, in contrast to the original example, may be classified as a high-grade neoplasm. A 92-year-old man presented with an ulcerated lesion on the left ear. The tumor was excised, and the patient had no evidence of recurrence or metastasis 6 years after surgery. Microscopically, the neoplasm demonstrated a fenestrated growth pattern with a slightly myxoid matrix in the background. Two clear components were identified: the first component was clearly epithelial with formation of small round nests, lobules, delicate strands, and small cribriform structures of basaloid cells with some degree of peripheral palisading, nuclear atypia, focal nuclear crowding, and frequent mitotic figures including abnormal forms. Each epithelial aggregation was invariably surrounded by one to three rows of cells with oval to round nuclei, which appeared very similar to specific trichogenic stroma seen in anagen follicles or in trichoblastomas; however, these stromal cells manifested atypical mitoses and cellular pleomorphism. The epithelial and stromal units frequently formed structures identical to follicular papillae associated with germs or "continuous germs" contiguous with "continuous papillae." Despite the close association throughout the tumor, the epithelial and the stromal cells were sharply separated, without transition between both elements. In foci, these stromal cells lost their follicular papillae-like arrangement and proliferated in a diffuse fashion and gradually blended with highly pleomorphic mononuclear spindle-shaped cells and bizarre multinucleated cells that grew in sheets in a highly vascular stroma. Immunohistochemically, the epithelial component showed diffuse staining for cytokeratins (AE1/AE3) and was negative for vimentin and CAM5.2. The stromal cells were positive for vimentin and negative for cytokeratin markers (AE1/AE3) and desmin. We view the present case and that previously reported in 2004 as authentic carcinosarcomas, and not as metaplastic (sarcomatoid) basal cell carcinomas. This conclusion is reached after analyzing the embryological development of the hair follicle, its normal histology and the morphology of cutaneous adnexal tumors with follicular differentiation.     

Epithelioid cell histiocytoma--histogenetic and kinetics analysis of dermal microvascular unit dendritic cell subpopulations

BACKGROUND: Epithelioid cell histiocytoma (ECH), also known as epithelioid fibrous histiocytoma, is a peculiar dermal tumor, which can mimic melanocytic, vascular, epithelial, or other histiocytic lesions. Thought to arise from dermal dendrocytes, most ECH contain approximately 50% FXIIIa+ histiocytic dendrocytes, but not all lesional cells express FXIIIa. A putative fibroblastic component has not been characterized. METHODS: We analyzed the differentiation and cell kinetics of dermal microvascular unit cells in 12 previously reported ECH using antibodies to FXIIIa, CD68 (KP1), CD34, CD117, CD31, smooth muscle actin, collagen type 1 aminopropeptide, and MIB-1, using single and double immunostains. RESULTS: In ECH, many variably sized CD34/CD31+ tumor vessels with actin+ myopericytes were surrounded by epithelioid-to-dendritic cells of three types. About 5-80% were dendritic histiocytes that expressed FXIIIa but not CD31 or KP1. Fibroblasts, in some cases showing mild nuclear pleomorphism, were usually collagen type 1+, but CD34 and actin- in 11/12 cases. One 'early' ECH had 40% CD34+ epithelioid cells, admixed with 50% FXIIIa+ histiocytes. Most ECH had about 2-20% KP1+, CD117+ mast cells. Mast cell numbers increased with FXIIIa+ histiocyte numbers and the intensity of FXIIIa expression. MIB-1/FXIIIa double-labeling showed only rare cycling histiocytes, with numerous cycling fibroblasts and endothelial cells. CONCLUSIONS: Our findings support the impression that ECH is a vascular fibrous histiocytoma. The constituent cells appear to arise from the activation of resident microvascular CD34+ dermal fibroblasts and the accumulation of FXIIIa+ dendritic stromal assembly histiocytes. The CD34+ cells appear to differentiate toward collagenous fibrocytes in association with histiocytes and mast cells in forming collagenous stroma and vessels. ECH is a tumor composed of all requisite cell types consistent with the origin from the dermal microvascular unit.     

Symplastisches Hämangiom

BACKGROUND AND OBJECTIVE: Endothelial nuclear atypia is the hallmark of malignant vascular tumors. Pleomorphic nuclei of the muscular vessel wall and the adventitia are manifestations of degenerative phenomena and should not be misinterpreted as signs of malignancy. PATIENTS/METHODS: Three long-standing solitary superficial vascular tumors (61-year-old woman, 48- and 63-year-old men) were removed by primary excision. Sections were stained according to standard histologic and immunohistologic protocols. RESULTS: Symplastic hemangiomas show the silhouette of a small superficial angioleiomyoma or capillary hemangioma. Characteristic features are multinucleate cells of the muscular vessel wall and the adventitia with pleomorphic nuclei, broad hyalinized vessel walls, and the distinctive lack of endothelial nuclear atypia. Recurrences or metastases were not reported (follow-up of 9, 45 and 90 months). CONCLUSIONS: Symplastic hemangioma is a benign superficial hemangioma with histological features of a pseudomalignancy. The distinctive lack of endothelial nuclear atypia allows distinction from malignant vascular tumors.     

CD34-reactive myxoid dermal dendrocytoma.

Normal skin is composed in part of cells that express CD34. These include periadnexal spindle cells, vascular endothelial cells, and interstitial dendritic cells. We report on a tumor composed mainly of CD34-reactive spindle cells. A 66-year-old Japanese woman presented with a skin-colored, dome-shaped, cutaneous papule on her left palm that was 7 mm in diameter and had developed within the preceding 3 months. Light microscopic examination showed a well-circumscribed polypoid tumor consisting of spindle-shaped cells and thin collagen fibers arranged loosely in a fascicular pattern within a myxoid matrix. Immunohistochemically, most of the tumor cells stained strongly for CD34, but did not stain with antibodies to S-100 protein, smooth muscle actin, desmin, neuron-specific enolase, epithelial membrane antigen, or factor XIIIa. Staining for vimentin and CD68 was positive. We believe this lesion to be a CD34-reactive myxoid dermal dendrocytoma of a type that has not been described previously.     

Atypisches Fibroxanthom – eine nicht‐„histiozytäre” Neoplasie.

Summary: On account of the controversial histogenesis of atypical fibroxanthoma (AFX) we examined 9 typical cases of this tumor histologically and by immunohistochemistry. Histology revealed eroded, ill‐defined dermal lesions with a pleomorph‐storiform growth pattern, predominantly composed of pleomorphic cells with numerous, in part atypical mitoses and variably accompanied by monomorphous cells among them also spindle cell areas. Three of our specimens contained osteoclast‐like giant cells. Immunohistologically, lesions consistently expressed vimentin, focally in histological monomorphous spindle areas alpha smooth muscle actin and reacted focally with KP1 and stronger with Ki‐M1p also in histologically bland areas without atypia and mitoses, but were generally negative for keratin, desmin and S‐100 protein. The average Ki‐M1p positivity accounted for 10 – 20 % of cells, in single cases focally up to 60 %. In order to investigate the nature of this cell population, sections were co‐labeled with the proliferation marker MIB1. MIB1 positivity accounted for up to 40 % of cells, yet only very occasional ones exhibited double staining with Ki‐M1p. Osteoclast‐like giant cells reacted with macrophage markers KP1 and Ki‐M1p, but not with MIB1. Thus, a macrophage differentiation of AFX appears to be excluded and the in part strong reactivity pattern for Ki‐M1p should best be regarded as an inflammatory background reaction against a neoplastic tissue destruction.     

儿童微静脉血管瘤一例

报告1例微静脉性血管瘤.患者女,8岁.因右食指褐黑色丘疹8年就诊.皮损组织病理检查:真皮中可见增生的薄壁小静脉,真皮胶原未见明显异常,胶原间隙可见散在血管内皮细胞,内皮细胞胞体饱满,无异形性.免疫组化染色显示:血管内皮细胞CD31、CD34及血管周围的细胞平滑肌动蛋白均阳性,而Ki-67阴性.符合微静脉性血管瘤的诊断.给予局麻下完全切除,目前随访无复发.该病主要需与早期的Kaposi肉瘤鉴别.

Abstract：

A case of microvenular hemangioma is reported.A 8-year-old girl presented with a 8-year history of a brown-black papule on the right forefinger.Histological examination showed numerous irregular,thin-walled,branching venules in the dermis with no abnormalities of collagen.In the space of collagen were plump endothelial cells without atypia.Immunohistochemical analysis of the vascular structures showed positive staining for CD31,CD34,smooth muscle actin (SMA),but negative staining for Ki-67.These findings are consistent with microvenular hemangioma,which should be mainly differentiated from Kaposi's sarcoma at early stage.The tumor was completely resected under local anesthesia,and no recurrence had been observed until the time of this writing.     

Pleomorphic angioleiomyoma

We describe two cases of pleomorphic angioleiomyoma. In one case, a 46-year-old man presented with a single nodule on his scrotum of 1 year's duration, and in another, a 38-year-old woman presented with a single nodule on her right knee of 1 year's duration. In both cases, histopathologic examination showed a well-circumscribed nodule composed of smooth muscle and numerous veins and capillaries. Contrary to the ordinary angioleiomyoma, marked nuclear pleomorphism was noted. Although mitoses were rare, immunohistochemistry revealed many tumor cells that were positive for proliferating cell nuclear antigen, Ki-67, and p53, indicating that the pleomorphic appearance does not simply represent a degenerative change of some tumor cells.     

The human progenitor cell antigen (CD34) is localized on endothelial cells, dermal dendritic cells, and perifollicular cells in formalin-fixed normal skin, and on proliferating endothelial cells and stromal spindle-shaped cells in Kaposi's sarcoma

The human progenitor cell antigen (CD34) is selectively expressed on hematopoietic progenitor cells in the bone marrow. In either cryostat sections of snap-frozen skin, or formalin-fixed paraffin-embedded sections of normal skin, anti-CD34 monoclonal antibody immunostained vascular endothelial cells and perivascular/interstitial dendritic cells, particularly in the reticular dermis. A distinctive population of perifollicular spindle-shaped cells in the midportion of the follicle (ie, bulge area), which is the site of the putative hair follicle stem cells, were CD34 positive, as were spindle-shaped cells in and around the eccrine glands accentuating their basement membrane zone. In patch/plaque--and tumor-stage acquired immunodeficiency syndrome-associated Kaposi's sarcoma lesions, CD34 expression was present on both the proliferating endothelial cells as well as the spindle-shaped stromal cells. CD34 positive endothelial cells and spindle-shaped stromal cells may play important participatory and supportive functions in both normal and diseased skin.     

复发性恶性纤维组织细胞瘤

报告1例切除14年后复发的恶性纤维组织细胞瘤。患者男，62岁。14年前行右胫前恶性纤维组织细胞瘤切除术，术后恢复良好。3个月前右胫前原手术部位又出现一肿块，逐渐增大，3d前肿块表面皮肤破溃，无明显自觉症状。肿块组织病理检查：肿瘤细胞排列呈梭形或星形，可见核分裂相及核瘤巨细胞，肿瘤细胞位于黏液样基质中，间质血管丰富，出血明显。     

An immunohistochemical analysis of radiation fibroblasts

A commonly recognized feature of chronic radiation dermatitis is the presence of mesenchymal cells with large atypical nuclei known as radiation fibroblasts. Little is known about their lineage or potential for neoplastic transformation. To investigate these properties, we examined 16 biopsy specimens in which radiation fibroblasts were present with antisera to mesenchymal determinants (FXIIIa, CD34, HHF-35), a proliferation marker (Ki-67), and a tumor-suppressor protein that is overexpressed in many cancers (p53). Radiation fibroblasts were largely negative for the markers of lineage that we employed – only 2 of 16 specimens showed strong expression of FXIIIa, with weak expression in another case. Scattered radiation fibroblasts expressed CD34 in one case. HHF-35 (muscle specific actin) stained small, dendritic cells in the superficial dermis, but not radiation fibroblasts. P53 was not detected within radiation fibroblasts in any of our cases, but was overexpressed by endothelial cells in 2 cases. Ki-67 stained rare endothelial and interstitial cells but not radiation fibroblasts. Radiation fibroblasts are immunophenotypically distinct from dermal dendrocytes and myofibroblasts. They appear to be non-cycling cells, and do not express high levels of p53 despite their marked nuclear atypia. Their phenotype argues against their possible role as progenitors of atypical fibroxanthoma (AFX) and dermatofibrosarcoama protuberans (DFSP) which are associated with ionizing radiation-induced skin damage.     

Hidroacanthoma simplex: an ultrastructural study

A non-invasive example of hidroacanthoma simplex that contained focal cellular atypia and abnormal mitoses occurred on the leg of an 80-year-old man. Ultrastructural features included abundant glycogen, peripheral tonofilaments and sparse short desmosomes. Nuclear profiles were smooth and nucleoli were dense and round. Thus, tumor cells were easily distinguished from the surrounding keratinocytes with which they formed short desmosomal junctions.     

Intramural schwannoma involving a vein

Schwannoma involving the blood vessels is a rare phenomenon. So far, only three cases of intravascular schwannoma have been described (all of which were intraluminal), and the origin of the schwannoma in such cases is not yet completely understood. Here, we describe a very rare intramural venous schwannoma in the subcutaneous right prepatellar area of a 31‐year‐old man. The schwannoma grew by enlarging and thickening the blood vessel wall, between two preserved layers of the vein. In some areas, there was erosion of the luminal layer, with fibrin apposed to the tumor. The tumor expressed S100 and was negative for CD31, CD34, desmin, and smooth muscle actin. The expression of p16 was preserved. Endothelial markers such as CD31 and Factor VIII showed the endothelial lining (which was D2‐40‐negative) above the tumor. Although degenerative atypia was present, there were no mitotic figures or necrosis identified.     

Recurrent atypical fibroxanthoma with satellite metastasis

Atypical fibroxanthoma (AFX) is a cutaneous neoplasm of uncertain etiology that develops on sun‐exposed regions of elderly males. It is widely considered to act indolently, despite its highly malignant cytologic features. Reports of metastatic AFX are very rare, and recurrence is uncommon. We report a case of recurrent AFX exhibiting a pattern of satellite metastasis followed by evidence of regional lymph node metastasis. A 76‐year‐old male with prior occupational and therapeutic radiation exposure and numerous squamous cell carcinomas had AFX of the left vertex scalp limited to the dermis completely removed by micrographic surgery. Twenty months later, multiple lesions appeared at the site of previous surgery. Imaging revealed no metastases or calvarial involvement. Wide local excision showed multiple well‐defined nodules involving dermis and subcutis. The primary and recurrent neoplasms were similar and composed of pleomorphic epithelioid and spindled cells with marked nuclear atypia, hyperchromasia and mitotic activity. Immunohistochemistry was positive for CD10, procollagen1 and vimentin and negative for cytokeratins AE1/AE3, cytokeratins 5/6, 34βE12, MNF116, p63 CD31, Mart1, smooth muscle actin, desmin, S100 and CD34. Forty‐eight months after removal of the primary, left intraparotid and posterior triangle lymph nodes are suspected to be involved by metastasis using clinical and positron emission tomography/ computed tomography examinations.     

Subungual leiomyoma in the left thumb of a 16‐year‐old female

Cutaneous leiomyomata, which are benign smooth muscle neoplasms, commonly present as dermal‐based nodules or papules with smooth borders and firm consistency. Digital, particularly subungual leiomyomata are quite rare. A 16‐year‐old female presented to nail clinic complaining of discoloration of the lunula of the left thumbnail for 2.5 months. On initial examination, a pink longitudinal band was present in the center of the nail plate, with yellow discoloration and distal onycholysis. The patient had only mild tenderness with firm palpation, and did not recall trauma of the area. A nail matrix biopsy was performed to determine the etiology of the lesion. Microscopic examination demonstrated a well‐demarcated dermal‐based spindle‐cell fascicular proliferation. Bland cells exhibited eosinophilic cytoplasm and elongate nuclei with blunt ends and minimal cytologic atypia. Prominent nucleoli, mitoses or necrosis were not appreciated. Immunohistochemical stains for smooth muscle actin and caldesmon highlighted the cells. Contrarily, S‐100, epithelial membrane antigen, p63, factor XIIIa, CD34, CD68 and p75 were all negative. Ki‐67 showed a low proliferative index. The immunoprofile combined with the morphologic features were interpreted as subungual leiomyoma. Subungual leiomyoma is a very rare diagnosis. We seek to bring awareness and expedite the diagnosis in patients with this lesion.     

A case of cutaneous symplastic leiomyoma - a rare variant of cutaneous pilar leiomyoma

We describe the case of a cutaneous symplastic leiomyoma in a 37-year-old woman who presented with a 4-year history of a painful slow growing lesion on the left upper arm. The lesion was excised and subjected to histological examination. A poorly circumscribed lesion was seen in the dermis composed of spindle shaped cells with marked nuclear pleomorphism. No mitotic figures or necrosis were seen. The cells stained strongly positive with desmin and smooth muscle actin, and negative with S100, melan A, MNF116 a mouse monoclonal antibody to cytokeratin and CK5/6. The diagnosis was felt to be in keeping with a cutaneous symplastic leiomyoma, a rarely reported variant of the pilar leiomyoma. Histologically, it shows features similar to the symplastic variant of uterine leiomyoma with cytological atypia, nuclear pleomorphism and minimal mitotic activity. Although the long-term outlook is probably benign, the presence of cytological atypia and mitoses in any spindle cell tumor is generally a concerning feature and warrants long-term follow up.     

Expression of the human hematopoietic progenitor cell antigen CD34 in vascular and spindle cell tumors

The human hematopoietic progenitor cell antigen is known as CD34. This antigen is present on normal bone marrow progenitor cells and vaseular endothelial cells. We used the monoclonal antibody auti-CD34 and immunoperoxidase staining techniques to evaluate the expression of CD34 in benign and malignant vascular and spindle cell tumors. All of the 42 vascular lesions, except two of three lesions of intravascular papillary endothelial hyperplasia, demonstrated diffuse membraneous staining of moderate lo strong intensity of their endothelial cells. Also, normal placentas (five) showed similar staining. All neurofibromas (12), three of five neuromas, and one of four neurilemmomas revealed moderate to strong, diffuse, membraneous staining. Five of eight piloleiomyomas, two of seven angiolciomyomas, and one of five uterine leiomyomas showed focal to dilluse, and weak to moderate, membraneous staining in the smooth muscle component. Six dermatofibrosarcoma protuberans were studied: generalized, strongly positive membraneous staining was present in four. All specimens showed staining of the normal endothelial cells and the cells surrounding the hair follicles (bulge area), sebaceous glands, and eccrine glands. No staining was demonstrated in any of the following fibrohistiocytic tumors: atypical fibroxanthomas (two), fibrous dermatofibromas (23), giant cell tumor of tendon sheath (one), and hemosiderotic dermatofibromas (18). Melanocytic tumors (Spitz nevi (three) and spindle cell superficial spreading malignant melanoma (one)], Merkel cell carcinomas (six), and spindle cell squamous cell carcinomas (two) did not stain with anti-CD34. Glomus tumors (two) and a hemangiopericytoma were also negative except for their vascular channels. This study demonstates that reactivity with anti-CD34 is not limited to normal vascular endothelial cells and their neoplasms.     

Macrophage-rich epithelioid angiosarcoma mimicking malignant melanoma

BACKGROUND: Cutaneous epithelioid angiosarcoma is a type of cutaneous angiosarcoma and usually arise both on the head or neck of the elderly. CASE REPORT: An 86-year-old male with an epithelioid angiosarcoma of the scalp that mimicked malignant melanoma. RESULTS: A large irregular dark grey-blue plaque with an adjacent speckled tan nodule was suggestive of a primary cutaneous malignant melanoma with adjacent in-transit metastasis. Both had a well-circumscribed growth pattern and were composed of numerous large epithelioid cells with scattered severe atypia and mitoses. The tumor was positive for S-100 protein and vimentin and negative for low- and high-molecular weight cytokeratins. However, at high power, the epithelioid cells with severe atypia were negative for S-100 protein, and abundant large epithelioid macrophages were responsible for the S-100 protein positivity. The malignant tumor cells were negative for HMB-45, positive for CD31 and Factor VIII-related antigen, and focally positive for CD34. A focus of infiltrative, classical angiosarcoma with irregular vascular channels lined with plump, anaplastic endothelial cells was then found deep to the epithelioid tumor. CONCLUSIONS: Macrophage-rich epithelioid angiosarcoma demonstrates abundant S-100 protein-positive epithelioid macrophages. This subset of epithelioid angiosarcoma may mimic malignant melanoma and may present as a pitfall in diagnosis.