Clinicopathological features and MYD88 L265P mutation status of intravascular large B cell lymphoma

Abstract

Objective: To study the clinicopathologic features and MYD88 L265P mutation status of intravascular large B cell lymphoma (IVLBCL). Methods: Fourteen cases of IVLBCLs were diagnosed from March 2014 to December 2019 at the First Affiliated Hospital of Zhengzhou University. The clinicopathologic features and prognosis were analyzed. Epstein-Barr virus encoded RNAs and MYD88 L265P mutation status were detected using in situ hybridization and Sanger sequencing, respectively. The follow-up data were obtained by telephone interview. Results: There were 6 males and 8 females with a median age of 62 years (range: 48-73 years). The involved anatomic locations were demonstrated by positron emission tomography-computed tomography, including adrenal gland (7/14), bone (6/14), central nerve system (4/14), skin (3/14), female reproductive system (3/14), local lymph nodes (3/14), prostate (2/14), liver and spleen (2/14), sphenoid sinus (1/14), penis (1/14), bladder (1/14), and right lung (1/14). Fever was the most common symptom (7/14), followed by neurologic symptoms and lower abdominal pain (2/14 each). The reminder symptoms included rash with edema, legs weakness and numbness, or postmenopausal bleeding (1/14 each). Eleven cases were at Lugano stage Ⅳ. Four cases were associated with the hemophagocytic syndrome, while 6 cases with bone marrow involved. Microscopically, the tumor cells were generally concentrated within the small-to-medium vascular lumens or sinusoids; they had centroblast-like appearance and showed large round or oval nuclei with slightly irregularities, coarse chromatin and 1-3 distinct nucleoli. One exception was the one case with an embryoid nuclei, reminiscent of anaplastic large cell lymphoma. The mitosis was not uncommon. Extravascular neoplastic cells were seen in two cases. The neutrophils could be appreciable in most of the cases (10/14). Immunophenotyping showed that CD20 and CD79α were diffusely and strongly positive in 14 cases; 12 cases were classified as the non-GCB subtype; 6 out of the 11 cases were double expressor lymphoma; 7 out of the 12 cases were CD5-positive. Twelve cases were EBER negative. The MYD88 L265P mutation was detected in 1 case (1/10). The duration of the follow-up ranged from 0.5 to 24.0 months, and 11 patients survived and 3 died. Conclusions: IVLBCL is rare. The most common type of IVLBCL in China is Asian type with scant tumor cells. Combination of clinical and immunohistochemical features can avoid most, if not all, misdiagnoses and missed diagnoses. Some IVLBCL cases may harbor the MYD88 L265P mutation, but the prevalence of MYD88 L265P mutation in the population still warrants additional studies.