Primary anaplastic lymphoma kinase-positive large B-cell lymphoma of the left bulbar conjunctiva: A case report

BACKGROUND Anaplastic lymphoma kinase (ALK)-positive large B-cell lymphoma (LBCL) is an aggressive and rare variant of diffuse LBCL. Herein, we report an uncommon case of stage IE extranodal ALK-positive LBCL initially originating in the bulbar conjunctiva. CASE SUMMARY A 63-year-old woman presented with a mass in the left bulbar conjunctiva that had persisted for six months, accompanied by swelling and pain that had persisted for 3 d. Eye examination revealed an 8 mm slightly elevated pink mass in the lower conjunctival sac of the left eye. Microscopically, the tumor was composed of large immunoblastic and plasmablastic large lymphoid cells with scattered anaplastic or multinucleated large cells. Immunophenotypically, the neoplastic cells were positive for ALK, CD10, CD138, Kappa, MUM1, BOB.1, OCT-2, CD4, CD45, EMA, CD79a, CD38, and AE1/AE3, and negative for CD20, PAX5, Lambda, BCL6, CD30 and all other T-cell antigens. The results of gene rearrangement tests showed monoclonal IGH/IGK/IGL and TCRD rearrangements. Fluorescence in situ hybridization studies did not reveal any BCL2, BCL6 or MYC rearrangements. Furthermore, Epstein-Barr virus was not detected by in situ hybridization in the lesions. Based on the histopathological and imaging examinations, the neoplasm was classified as stage IE ALK-positive LBCL. No further treatments were administered. At the 6, 15, and 21 mo postoperative follow-up visits, the patient was in good condition, without obvious discomfort. This case represents the first example of primary extranodal ALK-positive LBCL presenting as a bulbar conjunctival mass, which is extremely rare and shares morphological and immunohistochemical features with a variety of other neoplasms that can result in misdiagnosis. CONCLUSION Awareness of the condition presented in this case report is necessary for early and accurate diagnosis and appropriate treatment.