Involvement of bone marrow in lymphoma: pathological investigation in a single-center from northern China.

OBJECTIVES: This study aimed to evaluate key features of bone marrow trephine biopsy (BMT) involvement of lymphoma in Northern China. METHODS: 950 cases were assessed for the occurrence of bone marrow involvement and architectural features including volume percentage, involvement pattern (diffuse, nodular, focal, para trabecular, or interstitial), and presence/absence of background changes (granuloma, stromal fibrosis or necrosis). Correlations with bone marrow aspirate (BMA) and flow cytometry (FCM) findings were made in a subset of paired cases (359 BMA and 364 FCM). RESULTS: 153 (16.1%) cases involved BMT. The most frequent type was mantle cell lymphoma (28/153, 18.3%). Architectural features were similar to previous studies except that diffuse large B-cell lymphoma (DLBCL) preferred focal pattern (16/22 cases, 72.7%) most of all. BMA and BMT agreed in 84.1% of cases (302 of 359: 277 both negative, 25 both positive), while FCM and BMT agreed in 80.8% of cases (294 of 364: 242 both negative, 52 both positive). Both varied widely among different subgroups. CONCLUSIONS: Occurrence of BMT involvement by lymphoma in Northern China is relatively low. The volume percentage, distribution patterns and background changes may be useful pointers towards a particular lymphoma type in Chinese. FCM is more sensitive and reliable than BMA in China.