A case of a Ki-1 large cell anaplastic lymphoma with ultrastructural features

CD13-positive anaplastic large cell lymphoma of T-cell origin--a diagnostic and histogenetic problem

The expression of myelomonocytic-associated antigens in anaplastic large cell lymphomas (ALCLs), particularly those presenting in extranodal sites, can make their distinction from extramedullary myeloid cell tumors (EMCTs) or histiocytic tumors problematic. Yet, this distinction is clinically significant because of its therapeutic and prognostic implications. Herein, we describe a case of extranodal anaplastic lymphoma kinase-positive CD30-positive ALCL of T-cell origin in a 12-year-old boy, which was initially called an EMCT because of the expression of CD13 and HLA-DR detected by flow cytometry and the absence of other T-cell-related surface markers. However, the detection of cytoplasmic CD3 by flow cytometry prompted further studies. The tumor was composed of large cells with abundant slightly eosinophilic vacuolated cytoplasm and ovoid or reniform nuclei with a few small nucleoli. Using immunohistochemistry, the tumor was positive for CD45, CD30, CD45RO, and CD43 with a strong cytoplasmic and nuclear anaplastic lymphoma kinase stain. The tumor cells showed a T-cell clonal genotype. Electron microscopy revealed no ultrastructural features of myelomonocytic or histiocytic origin. The patient responded well to the chemotherapy and was in complete remission for 10 months at the time of submission of this manuscript. Review of the literature showed inconsistencies regarding the diagnosis, nomenclature, and, therefore, treatment and prognosis of these tumors. In addition, the CD13 expression in ALCL raises some histogenetic questions and may indicate origin from a pluripotent stem cell, misprogramming during malignant transformation, or a microenvironmental effect on lymphoid cell expression of surface antigens. Therefore, ALCL should be considered in the differential diagnosis of EMCTs or histiocytic tumors, particularly when surface marker lineage assignment is ambiguous.

Recurrent cervical lymphadenopathy due to Ki-1 lymphoma in an elderly female

A 70-year-old female presented with recurring cervical lymphadenopathy over a 5-year period. Intermittently, symptoms of respiratory and GI tract disease occurred, raising the possibility of malignancy. Investigation of these systems and of the breasts were negative. A lymph node biopsy was eventually done and showed intrasinusoidal proliferations of CD30-positive malignant cells which were also characterized ultrastructurally. Therapy with CHOP has produced a good initial response. The value of electron microscopy in diagnostic pathology is illustrated.

Primary gastric Ki-1 positive anaplastic large cell lymphoma: a report of two cases

Two cases with primary gastric Ki-1 positive anaplastic large cell lymphoma are presented. Morphologic features of both cases involved pleomorphism of the neoplastic cells, fibrosis and lymphatic infiltration. The neoplastic cells in both cases were positive for BerH2 (CD30), LCA(CD45), lysozyme and alpha-1-antitrypsin (alpha 1-AT). In additional case, the neoplastic cells were additionally positive for MAC387 and alpha 1-antichymotrypsin (alpha 1-ACT). The neoplastic cells in these cases were negative for L26(CD20), UCHL-1(CD45RO), DAKO CD3 and epithelial membrane antigen (EMA). According to the results of the phenotypic studies, the authors consider that the neoplastic cells have some of the features of histiocytes. Both patients at 2 and 8 years after surgery without chemotherapy are disease free. This lymphoma is well known to be frequently misdiagnosed as undifferentiated carcinoma. Although rare in occurrence, recognition of this primary lymphoma in the stomach has a significant clinical implication, as the authors consider that its prognosis might be better than undifferentiated carcinoma of the stomach.

KP1 (CD68)-positive large cell lymphomas: a histopathologic and immunophenotypic characterization of 12 cases

CD68/KP1 antigen expression in a series of 298 non-Hodgkin's lymphoma (NHL) cases, including 41 cases of CD30/Ki-1-positive anaplastic large cell (Ki-1+ ALC) lymphomas, was examined. Among the cases in this series, 12 large cell NHLs, including five centroblastic (G group according to the Working Formulation) NHLs, three immunoblastic (H group) NHLs, and four Ki-1+ ALC lymphomas, were found to express KP1. By extensive immunophenotypic analysis and in situ hybridization, KP1-positive large cell lymphomas of the G and H groups were assigned a B-cell phenotype. The pattern of KP1 staining usually consisted of localized small to medium-sized cytoplasmic dots; only two cases showed diffuse fine granular reactivity. In two of the four Ki-1+ ALC lymphomas tumor cells failed to express a B- or T-cell phenotype and stained positively for lysozyme, whereas in the other two cases they showed a hybrid T/histiocytic, phenotypic profile. KP1 staining of Ki-1+ ALC lymphoma cells was usually intense and showed a diffuse granular cytoplasmic pattern; tumor cells also expressed the CD13 antigen and showed strong reactivity with the anti-CD68 EBM11 antibody. Our results suggest that certain subsets of large "blastic" B-cell lymphomas may simultaneously express the CD68/KP1 histiocyte-specific marker and other myeloid-associated antigens, indicating the necessity of using a multiparameter approach in the determination of cell lineage. Moreover, this study, which demonstrates that the expression of CD68/KP1 and CD30 antigens is not mutually exclusive, supports the view that a fraction of cases diagnosed as Ki-1+ ALC lymphomas (at least those with KP1 expression along with the lack of B- or T-antigen expression) represent true histiocytic lymphomas despite the Ki-1+ phenotype.

Immunohistochemistry of Hodgkin and non-Hodgkin lymphomas with emphasis on the diagnostic significance of the BNH9 antibody reactivity with anaplastic large cell (CD30 positive) lymphomas

BACKGROUND

Morphologic and immunohistologic studies were performed on a series of 213 lymphoma cases, including CD30-positive anaplastic large cell (ALC) lymphomas (45 cases), other CD30-positive (18 cases) or CD30-negative (72 cases) non-Hodgkin lymphomas (NHL), cases of Hodgkin disease (HD) (73 cases), and an additional 5 cases exhibiting features of both CD30-positive ALC and Hodgkin lymphomas.

METHODS

The aim was to assess differential expression by tumor cells of CD30/BerH2, epithelial membrane antigen (EMA), and other monoclonal antibodies, including BNH9, an epithelial and endothelial marker that has been found to be reactive with ALC lymphoma cells.

RESULTS

A significantly greater proportion of cases of ALC lymphoma compared with HD exhibited positive results for CD45, EMA, CD45RO, and CD3 in CD30-positive atypical large cells, whereas Reed-Sternberg cells in HD most frequently coexpressed CD15 and CD30 antigens. ALC lymphoma cells reacted with BNH9 MoAb in 10 of the 42 (23.8%) assessable cases, whereas Reed-Sternberg cells reacted with this antibody in 5 of 73 (6.8%) HD cases. Only 3 of 90 (3.3%) NHL cases had positive results for BNH9; they were CD30-negative high-grade or low-grade lymphomas. It was noteworthy that 9 of 10 BNH9-positive ALC lymphomas also were EMA positive. Four of the five cases with morphologic features intermediate between those of HD and ALC lymphoma showed immunohistologic findings (positive results for CD30 and CD15, negative results for EMA, CD45, and BNH9) similar to those frequently observed in the HD cases; conversely, the remaining case showed a profile (positive results for CD30, CD45, and EMA, negative results for CD15) typically observed in ALC lymphomas.

CONCLUSIONS

This study suggests that the differential expression of CD45, EMA, and CD15 could be used in the distinction of ALC lymphomas and HD, whereas it seems that BNH9 antibody reactivity may be of diagnostic use only in that it reinforces the diagnostic value of EMA expression in the differentiation of these entities.

Ki-1 large cell lymphoma with regressing lesions in a child

An 8-year-old boy was seen with a cutaneous Ki-1 anaplastic, large cell lymphoma with multiple lesions. Some of the lesions showed spontaneous regression. During more than seven years of disease no systemic involvement was observed, but recurrent, self-healing lesions did appear. Histopathologic examination of five lesions revealed a variety of findings, from an inflammatory infiltrate to a highly anaplastic pattern. The neoplastic cells expressed Ki-1 and leukocyte common antigens. Ultrastructurally, those cells showed ruffled indentations. The differential diagnosis includes microvillous malignant lymphoma. The patient has had a four-year follow-up without relapses.

Anaplastic large cell Ki-1 lymphoma of the stomach with villopodial projections: an immunocytochemical and ultrastructural study and review of the literature

The report describes a case of anaplastic large cell Ki-1 lymphoma of the stomach with a rapidly fatal course observed in a 28-year-old woman. By electron microscopy the neoplastic cells presented long projections of the cytoplasmic membrane arranged uniformly along all the cell circumference. The morphology and distribution of these projections were characteristic, and the term villopodial is proposed for them. A review of the literature revealed 18 cases of lymphoma and 7 cases of nonlymphoid neoplasms composed of cells with projections similar to those observed in the present case. It is suggested that such tumors be denominated villopodial lymphomas and villopodial tumors. The present case is the first anaplastic large cell Ki-1 lymphoma with villopodial projections reported in the literature.

Fine-needle aspiration biopsy of Ki-1-positive anaplastic large-cell lymphoma

Five cases of Ki-1-positive anaplastic large-cell lymphoma diagnosed by fine-needle aspiration biopsy are reviewed, and cytologic, histologic, and ultrastructural findings in these cases are correlated. In all cases, the diagnosis of anaplastic large-cell lymphoma was suggested on the basis of the morphological appearance in aspiration smears. This diagnosis was confirmed by immunohistochemistry, which revealed strong positivity of most of the cells by Ki-1 antibody. Two of the lymphomas were T-cell type, one was B-cell type, and the remaining 2 were composed of null cells. In 2 cases, intracytoplasmic inclusions were seen in some of the tumor cells in aspiration smears. These were ultrastructurally correlated with large lysosomal bodies of variable morphology. Fine-needle aspiration combined with immunohistochemistry may be an effective technique for diagnosing this neoplasm.

Ki-1 lymphoma: a case report

A case of Ki-1 lymphoma of the large cell anaplastic type with weak leukocyte common antigen expression is presented. These tumors can sometimes demonstrate confusing immunophenotypes (weak or negative leukocyte common antigen, pan T, pan B, HMB 45, and S-100, and anomalous positive epithelial membrane antigen staining), and ultrastructural examination may be requested. The tumor consisted of sheets of large malignant cells with large pleomorphic nuclei, prominent nucleoli, and a high mitotic rate. Ultrastructural examination showed pleomorphic tumor cells with irregular nuclei, large nucleoli, and abundant complex cytoplasm with varied organelles.

Large cell anaplastic lymphoma: evaluation of immunophenotype on paraffin and frozen sections in comparison with ultrastructural features

Eleven cases of large cell anaplastic lymphoma (T type n = 5, B type n = 4, 0 type n = 2) were investigated using electron microscopy and immunophenotyping on formalin-fixed paraffin sections and frozen sections of fresh tissue, to determine whether morphological criteria exist for the discrimination of T, B, and 0 phenotypes. Tumour cell lineage could not be established from ultrastructural features. On paraffin material monoclonal B-cell markers Ki-B5 and L-26 served as reliable tools for recognizing the B phenotype of large cell anaplastic lymphomas (previously determined on fresh material). whereas monoclonal antibodies MT1 (CD43) and UCHL1 (CD45RO) were of limited value in lineage determination.

Clinicopathologic study of large cell anaplastic lymphoma (Ki-1-positive large cell lymphoma) among the Japanese

The clinical, prognostic, phenotypic, and genotypic findings of 30 patients with large cell anaplastic lymphoma (Ki-1-positive large cell lymphoma) were analyzed. There were 13 male and 17 female patients (male-female ratio, 0.8) whose ages ranged from 3 to 81 years of age (mean, 28 years of age; 67% of the patients younger than 30 years of age). The 5-year survival rate was 52%; this was better than that of other types of high-grade peripheral T-cell lymphoma. Histologic examination showed distinctive morphologic features such as tumor cell pleomorphism, sinus infiltration, fibrosis, partial lymph node involvement, sparing of B-cell regions, and occasional plasma cell infiltrates. Eighty percent of the cases were of T-cell phenotype, and others expressed neither B-cell nor T-cell markers. The tumors were frequently positive for a histocompatibility antigen (HLA-DR), CD25 (the interleukin-2 receptor), and epithelial membrane antigen. Rearrangements of the T-cell receptor beta gene were observed in nine of 13 cases (69%). These findings indicated that many of the tumors had the phenotype and genotype of activated T-cells. This study also showed that large cell anaplastic lymphoma has a survival figure intermediate between Hodgkin's disease and low-grade peripheral T-cell lymphoma.

Long-term survival in Ki-1 lymphoma

Three patients with histologic and immunologic features of Ki-1-positive large cell lymphoma, who experienced long-term survival, are presented. These three patients at 2, 28, and 49 years of age had adenopathy; all cases had been initially misdiagnosed as metastatic carcinoma or malignant histiocytosis. On subsequent review, they had sinusal and diffuse growth of large pleomorphic cells that were Ber-H2 (Ki-1; CD 30) positive. One case marked as a T-cell lymphoma with UCHL1, one case expressed T-cell and B-cell markers, and one case was negative for both T-cell and B-cell markers. All patients received chemotherapy, and two received local radiation. One patient was not treated until 9 years after initial diagnosis. Two patients had several recurrences, but there has been no evidence of lymphoma in any of the three patients for 63 to 301 months; overall survival time has ranged from 14 to 25 years. These cases are the longest reported survivors with Ki-1 lymphoma; 5 years was the longest survival time previously reported. It also is noteworthy that Ber-H2 and other lymphoid-associated antigens appear to be preserved in formalin-fixed, paraffin-embedded tissues for prolonged periods. This may allow retrospective studies to evaluate the natural history of Ki-1 lymphomas, as well as their spontaneous or treatment-induced regression.

Histopathologic, immunophenotypic, and genotypic analysis of Ki-1 anaplastic large cell lymphomas that express histiocyte-associated antigens

CD30/Ki-1 antigen expression in 243 cases of malignant lymphomas was examined using Ber-H2 monoclonal antibody. Among them 20 cases were categorized as Ki-1 anaplastic large cell lymphoma. In two of these cases histiocyte-associated markers were also expressed. In these cases histopathologic and extensive in situ immunophenotypic analyses were used with genotypic studies in the determination of cell lineage. A sinusoid histologic pattern of involvement with partial lymph node infiltration by pleomorphic neoplastic cells was noticed in the nodes from both patients. Solid areas of node replacement resembling metastatic carcinoma were seen in Patient 1. Immunohistologically, tumor cells of both cases were positive for CD30, CD25, CD71, LN3 (HLA-DR), EMA, CD45, CD74, vimentin, alpha-1-antichymotrypsin, and CD68. Patient 1 was also CD45RO+, CD43+, whereas Patient 2 was positive for alpha-1-antitrypsin and CD4 tumor cells. Genotypic studies revealed that TCR beta and TCR gamma chain genes were clonally rearranged in Patient 1, whereas no rearrangements were detected in Patient 2. This study supports the view that some Ki-1 anaplastic large cell lymphomas may express multiple histiocyte-associated antigens and confirms that this group of neoplasms have immunophenotypic heterogeneity. The results of genotypic analyses used with immunophenotyping does not exclude that the tumor cells in these cases may be of true histiocytic origin despite the Ki-1-positive phenotype.

Ultrastructure of 26 cases of Ki-1 lymphomas: morphoimmunologic correlation

Twenty-six cases of high-grade lymphomas with activation markers (CD30) classified and immunophenotyped according to the Kiel classification were studied to determine their fine structural features. Transmission electron microscopy showed in 17 cases anaplastic nuclear and cytoplasmic changes identical to those observed in Hodgkin's disease, it being impossible to determine by the morphology a B, T, or null nature. Four high-grade B-centroblastic and immunoblastic cases and five T-pleomorphic cases showed nuclear changes and cytoplasmic differentiation that suggested a T or B nature. An immunogold-labeling technique showed CD30-positive particles primarily in the Golgi complex and occasionally in the cell membrane.