bromochloroacetic-acid and Lymphoma--Large-Cell--Anaplastic

Anaplastic large cell lymphoma has histopathologic features that necessitate a broad differential diagnosis. Diagnostic considerations include carcinoma, melanoma, and hematopoietic malignancies, including diffuse large B-cell lymphoma, classical Hodgkin lymphoma, myeloid sarcoma, and peripheral T-cell lymphoma, not otherwise specified. Unusual features can include subtle sinusoidal involvement, histiocytic morphology, cytokeratin expression, CD15 expression, and variant patterns of anaplastic lymphoma kinase expression. Cases with unusual morphologic or immunohistochemical findings will be presented to highlight the complexity encountered in practice.

Topics: Diagnosis, Differential; Histiocytes; Humans; Immunohistochemistry; Keratins; Lymph Nodes; Lymphoma, Large-Cell, Anaplastic; Neoplasm Proteins

An 81-year-old male presented with a rapidly growing cheek nodule. Biopsy revealed a dermal infiltrate of large atypical cells, some exhibiting a horseshoe-shaped nucleus. Immunohistochemistry revealed positivity for CD4, CD3, CD45, and CD30 (>95%). Melanocytic markers, cytotoxic markers, CD20, CD56, ALK1, synaptophysin, CD1a, and ETS-related gene (ERG) were negative. Notably, there was weak but diffuse expression of pan-cytokeratin (AE1/AE3) and Oscar keratin. There was also a weak expression of epithelial membrane antigen (EMA). CAM 5.2, p40, and IRF4/DUSP22 rearrangement were negative. Further staging revealed skin-limited disease. A diagnosis of primary cutaneous anaplastic large-cell lymphoma (PC-ALCL) was rendered. We present a rare case of cytokeratin positive PC-ALCL, a finding never reported in the literature. Both PC-ALCL and systemic ALCL (S-ALCL) evoke a broad differential. CD45, EMA, and cytokeratin stains help differentiate from metastatic carcinomas. There have been rare prior reports of cytokeratin expression in S-ALCL, which tend to stain with an unusual cytoplasmic and membranous pattern like our case, have variable co-expression of EMA, and null T-cell phenotypes. These show the significant diagnostic challenges that can arise in differentiating ALCL from metastatic or primary skin carcinomas. Awareness, careful attention to morphology (e.g., hallmark cells), and considering routine CD30 can help lead the pathologist to the correct diagnosis.

Topics: Aged, 80 and over; Humans; Keratins; Lymphoma, Large-Cell, Anaplastic; Male; Mucin-1; Skin Neoplasms

Topics: Humans; Keratins; Ki-1 Antigen; Lymphoma, Large B-Cell, Diffuse; Lymphoma, Large-Cell, Anaplastic; Receptor Protein-Tyrosine Kinases

Cytokeratin (pan) and epithelial membrane antigen (EMA) were considered as commonly useful epithelial markers to distinguish cancer from lymphoma, but the expression of cytokeratin (pan) and EMA had also been seen in some lymphomas. Here, we presented an unusual case of anaplastic large cell lymphoma (ALCL) absence of some lymphoid markers (Including CD3, CD20, Pax-5, CD45Ro) and positive for cytokeratin (pan) and EMA, which was misdiagnosed as metastatic carcinoma. Our case suggested that the epithelial markers (including cytokeratin and EMA) show an overlap with that of ALCL, which represented a diagnostic pitfall for confusing ALCL with metastatic carcinoma.

Topics: Adult; Biomarkers, Tumor; Biopsy; Diagnostic Errors; Humans; Intracellular Signaling Peptides and Proteins; Keratins; Ki-1 Antigen; Lymph Nodes; Lymphatic Metastasis; Lymphoma, Large-Cell, Anaplastic; Male; Mucin-1; Proteins

Topics: Carcinoma; Diagnosis, Differential; Female; Humans; Immunohistochemistry; Keratins; Lymphoma, Large-Cell, Anaplastic; Middle Aged; Neoplasms, Unknown Primary

This report analysed the phenotype of fourteen cases of Ki-1-positive anaplastic large cell lymphoma, recently described high-grade malignant lymphoma. In 12 cases the neoplasm involved lymph nodes, two patients presented with primary extra-lymphoid involvement (stomach, larynx), whereas secondary involvement of the skin was observed in one patient. Immunohistochemical study revealed B-cell phenotype in seven cases; three cases presented T-cell specific markers; in three cases we found antigens characteristic for both lymphoid lineages and one case presented null phenotype. Ki-1 (CD30) antigen was found in every of 14 cases, and LeuM1 (CD15) antigen was not expressed in any of studied cases. In two cases we revealed the expression of cytokeratins (CAM 5,2). The foregoing results confirm heterogeneity of this neoplasm and suggest careful interpretation of the results of morphologic and immunohistochemical findings in any pleomorphic and anaplastic tumour.

Topics: Adult; Aged; Aged, 80 and over; Biomarkers, Tumor; Female; Humans; Immunohistochemistry; Keratins; Lymphoma, Large-Cell, Anaplastic; Male; Middle Aged; Phenotype; Retrospective Studies