摘要:

Extranodal marginal zone B-cell lymphoma (MZBL) is a recently recognized low-grade lymphoma that has been well described in other organs such as the stomach and salivary gland. It has only recently been described in skin, where it may be difficult to distinguish from reactive processes and other types of B-cell lymphoma such as follicle center lymphoma. These cases may have been classified as pseudolymphomas in the past. Extranodal MZBL was referred to as mucosa-associated lymphoid tissue (MALT) lymphoma before the Revised European-American Classification of Lymphoid Neoplasms was published in 1994. Important histologic features that aid in the diagnosis of MALT lymphoma are atypical lymphocytes (centrocyte-like and monocytoid B cells) often admixed with plasmacytoid lymphocytes, a prominent plasma cell component, lymphoepithelial lesions, intranuclear inclusions (Dutcher bodies), and reactive germinal centers that may be colonized by neoplastic cells. Immunophenotypic studies demonstrating a B-cell phenotype, light chain restriction, coexpression of CD43, and staining of atypical lymphocytes with bcl-2 support a diagnosis of MALT lymphoma. We studied 11 cases of extranodal MZBL of the skin from the Armed Forces Institute of Pathology files. There were six women and five men ranging in age from 30 to 69 years (median, 54 years). The anatomical sites included the trunk, head and neck areas, and upper extremities. There were no other sites of disease besides the skin in any of the cases. The follow-up period ranged from 5 months to 8 years (median, 24 months). Histologic results included an atypical lymphoid infiltrate with B-cell phenotype, reactive germinal centers, and a variable plasma cell component in all cases. No Dutcher bodies or lymphoepithelial lesions were noted. Extranodal MZBL of skin is a diagnostic challenge because of a heterogeneous cellular infiltrate that may be interpreted as a reactive process. The most significant neoplasm with which it is confused is follicular lymphoma. It is important to recognize the characteristic histologic and immunophenotypic features of extranodal MZBL so that the appropriate therapeutic approach may be applied.

ISSN:0193-1091    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Large numbers of CD30-positive tumor cells are not typically observed in mycosis fungoides (MF), but CD30 expression may occur on large cells of MF that have transformed into high-grade large cell lymphoma. Of 202 patch/plaque phase MF cases studied by immunohistochemistry, we encountered 4 patients with patch-phase MF at stage Ia or Ib, whose lesions contained a high proportion (greater than 50%) of CD30-positive tumor cells within the epidermis. The morphologic and immunohistochemical features of these four cases were otherwise similar to those of other patch-phase MF cases, and were different from those of pagetoid reticulosis. More importantly, the clinical behavior of these cases did not differ from that of other cases of early MF without CD30 expression. The mechanism underlying the high levels of CD30 expression by epidermotropic tumor cells is unknown. With increased use of the CD30 immunohistochemical stain in the diagnosis of cutaneous lymphomas, similar cases are likely to be encountered, and perhaps will be evaluated for their clinical behavior.

ISSN:0193-1091    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Among thousands of specimens of melanocytic nevi, not including giant congenital melanocytic nevus or blue nevus, 42 melanocytic nevi that showed peripheral nerve sheath differentiation were collected. The patterns of melanocytic nevi with peripheral nerve sheath differentiation may be classified into three groups: 1) “neurotized and neural nevi” with nests of “neuroid cords” and “nevic corpuscles” (the most common pattern); 2) nerve fascicle-like structures with no relation to neurotized and neural nevi; and 3) palisading melanocytes of a nevus in nests of conventional melanocytic nevi (a rare pattern). Each pattern may represent a different expression of nerve sheath differentiation in melanocytic nevi. Some melanocytic nevi with nerve fascicle-like structures show discrete structures closely resembling authentic nerve fascicles, confirming a close relationship between melanocytes and peripheral nerve sheath cells (Schwann cells and probably perineurial cells in part) and suggesting derivation of the two types of cells from common precursor cells of the neural crest and their de novo development in the dermis rather than byAbtropfungof melanocytes from the epidermis. In addition, the high prevalence of Unna, Miescher, and superficial congenital nevi in melanocytic nevi with peripheral nerve sheath differentiation suggests a different character or process for these congenital melanocytic nevi than for Clark and Spitz nevi (junctional and compound types).

ISSN:0193-1091    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Peripheral nerve sheath differentiation was studied in 120 specimens of blue nevi (112 specimens of “common” blue nevi and 8 specimens of “cellular” blue nevi). In 10 of 112 common blue nevi, fascicles of pigmented dendritic melanocytes or less pigmented spindle-shaped melanocytes with S-shaped nuclei were associated with wavy delicate collagen bundles. In 4 of these 10 specimens, the melanocytes showed a perifollicular arrangement. These nerve fascicle-like structures were seen in some cellular blue nevi (5 of 8 specimens). Structures closely resembling authentic nerve fascicles were not observed in common or cellular blue nevi. The fascicles with S-shaped nuclei and fibrillary collagenous tissue observed in blue nevi (which were well detected in the cellular type but rarely found in the common type) may be peripheral nerve sheath features and perhaps evidence that dermal dendritic melanocytes in the reticular dermis may have arisen within a peripheral nerve sheath milieu from primitive fibroblast-like precursors. Some of the examples presented here may be identical to those reported for “pilar neurocristic hamartoma” or “neurocristic hamartoma.” I also speculate on the pathogenesis of blue nevi based on the observations made in this study.

ISSN:0193-1091    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Histiocytic tumors can be confused with melanocytic nevi and malignant melanoma and vice versa. To explore the use of immunohistochemistry for this diagnostic problem, we examined the expression of S-100 protein, gp100 (the antigen recognized by HMB-45), tyrosinase (T311), Melan-A (A103), Factor XIIIa (FXIIIa), and CD68 in 10 juvenile xanthogranulomas (JXGs), five epithelioid histiocytomas (EHs), and 15 melanocytic nevi composed of large epithelioid cells. All epithelioid melanocytic nevi were immunoreactive for Melan-A, tyrosinase, and S-100 protein in most melanocytes. Four nevi were completely negative with HMB-45. Nine nevi had only a minor HMB-45–positive component in the superficial dermis. Two nevi were diffusely HMB-45–positive. Melanocytes in all nevi were completely negative for FXIIIa. Thirteen nevi were completely negative for CD68. Two nevi contained rare cells with weak staining for CD68. All 15 histiocytic proliferations were completely negative for Melan-A, tyrosinase, and gp100. They lacked expression of S-100 protein or had at most 10% immunopositive cells. In JXGs, most cells were strongly reactive for CD68, although only a few were positive for FXIIIa. In EHs, 40% to 60% of cells were immunoreactive for FXIIIa, and only 20% to 30% were positive for CD68. Our results demonstrate that Melan-A and tyrosinase are sensitive and specific markers to distinguish epithelioid melanocytic nevi from epithelioid histiocytic tumors.

ISSN:0193-1091    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Histologic specimens from 41 rabbits were studied for changes resulting from the manual injection of brown recluse spider venom. Major findings included a mixed inflammatory cell infiltrate, coagulative tissue necrosis, and vasculitis. All specimens demonstrated a well-delineated zone of eosinophilic staining recognizable as “mummified” coagulative necrosis of the epidermis and dermis. A dense band of neutrophils bordered the zone of necrosis. Immediately adjacent to the neutrophilic band, small vessel vasculitis was a universal finding. Degranulated eosinophils and neutrophils and macrophages filled with eosinophilic granules were common. Inflammatory foci were often centered on groups of lipocytes within the dermis. Large vessel vasculitis resembling that seen in polyarteritis nodosa was present deep to 7 of the 40 eschars. Large vessel vasculitis may contribute to the large zones of necrosis seen after some brown recluse spider bites. Eosinophils may play a role in tissue damage after envenomation.

ISSN:0193-1091    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

We stained benign melanocytic nevi and malignant melanoma with antibodies to melanoma antigen recognized by T cells (Mart-1) to determine if this was useful in differentiating benign from malignant melanocytic neoplasms. Forty-five primary malignant melanomas and 71 benign melanocytic nevi were stained with antibodies to Mart-1. Two cases of malignant melanoma metastatic to lymph node and three cutaneous metastases of malignant melanoma were also stained. The degree of staining was graded into diffuse positive staining, focal positive staining, and negative staining. Thirty-six of 45 primary malignant melanomas stained diffusely positive with antibodies to Mart-1. This included three of five desmoplastic malignant melanomas that showed positive staining. Four melanomas showed faint or focal positive staining. One of two metastases to lymph node showed strong positive staining and one showed no staining. All three cutaneous metastases showed diffuse positive staining. Sixty-one of 71 melanocytic nevi showed no staining or faint staining with antibodies to Mart-1. Ten of 71 melanocytic nevi showed strong positive staining. The majority of these were congenital nevi. Staining with antibodies to Mart-1 antigen was a useful marker of malignant melanoma. However, staining may also be seen in benign melanocytic neoplasms. The presence or absence of staining for Mart-1 antigen cannot be used to differentiate benign melanocytic nevi from malignant melanocytic tumors.

ISSN:0193-1091    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

This report focuses on two unusual cases of cutaneous leiomyosarcoma composed of sparse numbers of neoplastic cells embedded in abundant sclerotic stroma throughout the entire neoplasm. To the best of our knowledge, only one example of this rare lesion has been described previously as “sclerotic primary cutaneous leiomyosarcoma.” However, the resemblance of this tumor to other desmoplastic tumors of the skin is striking and, therefore, we propose the term desmoplastic leiomyosarcoma of the skin for this neoplasm. Because of the sparse cellularity and the abundant stroma, desmoplastic leiomyosarcoma of the skin can be easily misinterpreted, especially in small biopsies. It should be included in the differential diagnosis of inflammatory skin diseases associated with sclerosis, such as radiation dermatitis, and of desmoplastic tumors of the skin, including desmoplastic melanocytic nevus, desmoplastic melanoma, and desmoplastic squamous cell carcinoma.

ISSN:0193-1091    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

This is a case report of a woman who had chronic lymphedema on one leg and who developed a primary cutaneous large B-cell lymphoma of the leg at that site. She received radiotherapy and did not show any systemic involvement thereafter. Other neoplasms may appear in a clinical setting of chronic lymphedema, namely, lymphangiosarcoma (Stewart-Treves), melanoma, and metastatic carcinoma. There are four other reports in the English literature of cutaneous lymphoma arising in an extremity with chronic lymphedema.

ISSN:0193-1091    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Poromas have been classified as eccrine neoplasms, but several recent reports of poroid tumors with sebaceous, follicular, and apocrine differentiation have challenged this concept. We report a case of apocrine poroma with sebaceous differentiation. A 69-year-old man presented with an asymptomatic elevated erythematous plaque. Histopathology revealed cellular nests composed of cuboidal poroid cells and sebocytes. The nests varied in size and were entirely intraepidermally arranged in a growth pattern similar to that of hidroacanthoma simplex. Given the common embryologic origin of folliculosebaceous and apocrine units, we believe that this lesion represents an apocrine poroma with sebaceous differentiation.

ISSN:0193-1091    

出版商:OVID    

年代:2000

数据来源: OVID