There Are No Magic Bullets in Hematopathology: Even Immunostains for CD20 and CD3 Can Get You Into Trouble

Cervical radiculopathy as first presentation of CD3-positive diffuse large B-cell lymphoma of the cervico-thoracic junction

BACKGROUND

Diffuse large B-cell lymphoma (DLBCL) in rare cases can presents an unusual expression of CD3 T-cell specific antigen. We report the first case of a CD3-positive DLBCL of the cervico-thoracic junction presenting with persistent cervical radiculopathy.

CASE PRESENTATION

A 74-years-old male patient presented a severe and persistent right C8 radiculopathy associated with right-sided neck pain, progressive numbness and weakness of the right arm. The symptoms prominent during the night interfering with sleep and were resistant to anti-inflammatory drugs and cervical orthosis. Spine MRI showed a solid hypointense lesion on T2-weighted images and hyperintense on STIR sequences involving the epidural space at C7, T1 and T2. The patient underwent a C7-T1 decompressive laminectomy and left T2 hemilaminectomy with resection of the epidural tissue resulting in subtotal removal. Histology showed a DLBCL germinal center B-cell lymphoma with expression of CD3 T-cell specific antigen. Then the patient underwent adjuvant radiotherapy and chemotherapy consisting of R-CHOP protocol. At last follow-up (2 years) the patient is still in good clinical status (KPS = 80) with almost complete recovery of the cervical radiculopathy.

CONCLUSIONS

To our knowledge this is the first case of DLBLC GCB-like CD3 positive to present with radiculopathy.

A challenging case of lymphoproliferative disease in a cat

A 7-year-old male castrated Maine Coon cat presented with edema of the right hindlimb and a markedly enlarged right popliteal lymph node. A CBC showed a neutropenia of 1.5 × 10³ /μL. Radiographs and ultrasonographic examination were unremarkable. Cytology of the right popliteal lymph node revealed a mixed population of cells, consisting predominantly of medium to large plasmacytoid lymphocytes, low to moderate numbers of well-differentiated plasma cells and low numbers of small lymphocytes. Plasmacytoid lymphocytes had round nuclei with finely stippled chromatin and one prominent round nucleolus. Low numbers of binucleated cells and bizarre mitotic figures, and rare multinucleated cells were observed. Histopathologic examination of the lymph node showed effacement of the normal lymph node architecture by dense sheets of neoplastic cells. Round to polygonal tumor cells of intermediate size had a low to moderate amount of cytoplasm. Round to indented hyperchromatic nuclei were often eccentrically located and contained one distinct nucleolus. Anisocytosis and anisokaryosis were moderate and 21 mitoses/10 high power field (HPF) were present. Congo red staining was negative. High numbers of tumor cells were positive for lambda light chain immunoglobulin; moderate numbers stained positive for MUM-1. A clonal BCR gene rearrangement was detected with an immunoglobulin heavy chain target (IGH), immunoglobulin lambda light chain (IgL), and kappa deleting element (Kde). Differential diagnoses for the lymphoproliferative disease in this cat included lymphoplasmacytic lymphoma and myeloma-related disorder.

CD3-positive plasmablastic lymphoma reported in two cases: A potential diagnostic caveat

Plasmablastic lymphoma (PBL) is a rare aggressive subtype of mature large B cell lymphoma involving almost exclusively the extranodal regions particularly the oral cavity, frequently described in immunocompromised patients. PBL is characterized histologically by diffuse proliferation of large neoplastic cells resembling B immunoblasts or plasmablasts. The diagnosis of PBL can be difficult due to its ambiguous histopathological features mimicking most large cell lymphomas and lacking a distinctive immunophenotypic pattern. They typically lack expression of CD20 and CD79a but may express plasma cell marker, CD138. Aberrant immunoexpression of CD3, a T-cell marker in PBL in the absence of other B-cell markers is exceptionally rare, may potentially lead to incorrect interpretation. Herein, we report a case series of CD3-positive PBL of oral cavity in two individuals, which were initially misdiagnosed as high-grade T-cell lymphomas including extranodal NK/T-cell lymphoma, nasal type. Useful distinguishing clinical settings, histomorphological features, immunohistochemistry and molecular expression profiles of PBL are discussed.

CD3-positive diffuse large B-cell lymphoma relapses as CD3-negative large B-cell lymphoma: Loss of aberrant antigen expression in B-cell lymphoma after chemotherapy

Aberrant expression of CD3 on diffuse large B-cell lymphoma (DLBCL) is rare, and its mechanism and biological significance are currently unclear. Herein we report a case of Epstein-Barr virus-negative, CD3-positive DLBCL in a 53 year-old male, who had a remote history of renal transplantation. After standard chemotherapy, the patient was in clinical remission. He relapsed three years later, but at this time with apparent loss of CD3 expression. PCR-based IGK gene rearrangement studies demonstrated clonal amplicons with an identical nucleotide size between the primary and secondary DLBCL, confirming the clonal relationship despite their phenotypic differences. To our knowledge, this is the first case of CD3-positive DLBCL that demonstrated a loss of aberrant CD3 on relapse. The chronologic change in phenotype seen in this case suggests that the source of the patient's lymphoma relapse may arise from either a quiescent subclone without CD3 expression, or from an upstream neoplastic precursor cell.