bromochloroacetic-acid and Leukemia--Lymphocytic--Chronic--B-Cell

Atypical fibroxanthoma can mimic other tumors, particularly spindle cell squamous cell carcinoma and spindle cell or desmoplastic melanoma. We describe a patient with chronic lymphocytic leukemia who developed acantholytic squamous cell carcinoma on the face, which recurred and metastasized to a cervical lymph node. This tumor was at first diagnosed as atypical fibroxanthoma because of its histologic and immunostaining similarity. It showed weak or negative keratin cocktail staining and strong vimentin staining. However, a recurrent tumor was immunostained for high-molecular-weight keratin and showed strong positivity. Aggressive behavior of this squamous cell carcinoma may be due to altered immune response secondary to chronic lymphocytic leukemia.

Topics: Aged; Carcinoma, Squamous Cell; Diagnosis, Differential; Histiocytoma, Benign Fibrous; Humans; Immunohistochemistry; Keratins; Leukemia, Lymphocytic, Chronic, B-Cell; Lymphatic Metastasis; Male; Neoplasm Recurrence, Local; Neoplasms, Multiple Primary; Skin Neoplasms; Vimentin

Merkel cell carcinomas (MCC) not infrequently involve the periorbital region and the eyelids. Clinically, they are relatively characteristic but often unsuspected. Histologically, MCC are often misdiagnosed as lymphoma, melanoma, or metastatic small cell carcinoma of the lung (SCCL).. We present clinical, histological, and immunohistochemical data on six eyelid cases (all females; age 63-102 years; one with concomitant CLL) from our files of 77 MCC with special respect to differential diagnosis. For comparison, 22 SCCL were analyzed. Immunohistochemistry was done with antibodies against pan-cytokeratin (pan-CK), cytokeratin-20 (CK-20), neurofilament protein (NF), neuron-specific enolase (NSE), chromogranin (CHR), and S100 protein (S100).. Morphologically, five of six MCC were prototypic, one was of the small cell variant. Immunohistochemically, dot-like positivities for pan-CK and CK-20 were seen in all six MCC, and for NF in five tumors. None of the 22 SCCL stained positively for CK-20 or NF but 21/22 cases were positive for pan-CK. Only 1/21 SCCL showed dot-like patterns for pan-CK; 20/21 reacted diffusely. All MCC and 13/22 SCCL displayed CHR-positive cells. All MCC and all SCCL were positive for NSE and negative for S100.. Dot-like positivities for CK-20 or NF are important to prove MCC and to exclude SCCL in clinically and morphologically doubtful cases. Dot-like positivities for pan-CK favor MCC, but do not always exclude SCCL. NSE and CHR are of no value for the differential diagnosis of MCC and SCCL. Melanoma and lymphoma are ruled out by negativity for S100 and pan-CK, respectively.

Topics: Aged; Aged, 80 and over; Carcinoma, Merkel Cell; Carcinoma, Small Cell; Diagnosis, Differential; Eyelid Neoplasms; Female; Humans; Immunoenzyme Techniques; Keratins; Leukemia, Lymphocytic, Chronic, B-Cell; Lung Neoplasms; Middle Aged; Neurofilament Proteins; Phosphopyruvate Hydratase; S100 Proteins

Monoclonal antibodies (mAbs) directed against the leucocyte common (CD45) antigen have been proposed as a useful tool for the differential diagnosis between malignant lymphomas (CD45+) and poorly differentiated nonhemopoietic tumors (CD45-). Thanks to the availability of mAbs directed against fixative-resistant epitopes of the CD45 molecule, this distinction can now easily be made even in routinely processed tissues. However, a small percentage of morphologically poorly defined neoplasms are difficult to diagnose even with the help of immunohistochemistry. The investigators report that 63 out of 165 anaplastic large-cell (ALC) lymphomas did not show any reactivity for the CD45 antigen in paraffin sections. In routine biopsies, the lymphomatous nature of these cases, most of which had been sent for consultation, could be always unequivocally established by demonstrating negativity for cytokeratins (mAb KL1) and clear dot-like and/or surface reactivity with the Ber-H2 mAb, which is directed against a fixative-resistant epitope of the lymphoid cell activation antigen CD30. Strikingly, 54% of the CD45-cases reacted with mAbs directed against fixative-resistant epitopes of the T cell-restricted CD45RO antigen (mAb UCHL1) or the B-restricted molecules CD45RA (mAb 4KB5) and L26 (unclustered). In order to avoid confusion of ALC lymphomas with anaplastic nonlymphoid tumors, pathologists must be aware of the existence of CD30+/CD45- ALC lymphomas, as they can mimic the above-mentioned malignancies both morphologically (due to the sinusoidal growth pattern) and phenotypically (due to the expression of EMA). The investigators conclude that the combined use of mAbs directed against fixative-resistant epitopes of the CD30, CD45RO, CD45RA, and L26 antigens and cytokeratins is essential for the correct diagnosis and treatment of these equivocal cases.

Topics: Antibodies, Monoclonal; Antigens, Differentiation; Antigens, Neoplasm; Diagnosis, Differential; Epitopes; Histocompatibility Antigens; Humans; Immunohistochemistry; Keratins; Ki-1 Antigen; Leukemia, Lymphocytic, Chronic, B-Cell; Leukocyte Common Antigens; Lymphoma; Lymphoma, Large B-Cell, Diffuse; Paraffin