Cellular Classification of Adult Non-Hodgkin Lymphoma
Mediastinal large B-cell lymphoma (primary mediastinal large B-cell lymphoma)
Primary mediastinal (thymic) large B-cell lymphoma is a subset of diffuse large cell lymphoma characterized by significant fibrosis on histology.[119,120,121,122,123,124,125] Patients are usually female and young (median age 30–40 years). Patients present with a locally invasive anterior mediastinal mass that may cause respiratory symptoms or superior vena cava syndrome. Therapy and prognosis are the same as for other comparably staged patients with diffuse large cell lymphoma, except for advanced-stage patients with a pleural effusion, who have an extremely poor prognosis (progression-free survival is <20%) whether the effusion is cytologically positive or negative. (For information on superior vena cava syndrome and pleural effusion, refer to the Cardiopulmonary Syndromes summary.) High-dose chemotherapy with hematopoietic stem cell rescue has been applied to these poor prognosis patients. Evidence for this approach is anecdotal.
Follicular large cell lymphoma
The natural history of follicular large cell lymphoma remains controversial. While there is agreement about the significant number of long-term disease-free survivors with early stage disease, the curability of patients with advanced disease (stage III or stage IV) remains uncertain. Some groups report a continuous relapse rate similar to the other follicular lymphomas (a pattern of indolent lymphoma). Other investigators report a plateau in freedom-from-progression at levels expected for an aggressive lymphoma (40% at 10 years).[128,129] This discrepancy may be caused by variations in histologic classification between institutions and the rarity of patients with follicular large cell lymphoma. A retrospective review of 252 patients, all treated with anthracycline-containing combination chemotherapy, showed that patients with more than 50% diffuse components on biopsy had a worse OS than other patients with follicular large cell lymphoma. Treatment of these patients is more similar to treatment of aggressive NHL than it is to the treatment of indolent NHL. In support of this approach, treatment with high-dose chemotherapy and autologous hematopoietic peripheral stem cell transplantation shows the same curative potential in patients with follicular large cell lymphoma who relapse as it does in patients with diffuse large cell lymphoma who relapse.[Level of evidence: 3iiiA]
Anaplastic large cell lymphoma
Anaplastic large cell lymphomas (ALCL) may be confused with carcinomas and are associated with the Ki-1 (CD30) antigen. These lymphomas are usually of T-cell origin, often present with extranodal disease, and are found especially in the skin. The translocation of chromosomes 2 and 5 creates a unique fusion protein with a nucleophosmin-ALK. Patients whose lymphomas express ALK (immunohistochemistry) are usually younger and may have systemic symptoms, extranodal disease, and advanced stage disease; however, they have a more favorable survival rate than that of ALK-negative patients. Patients with these types of lymphomas are generally treated the same as patients with diffuse large cell lymphomas and have as good a prognosis as comparably staged patients, as evidenced in the GER-GPOH-NHL-BFM-90 trial. ALCL in children is usually characterized by systemic and cutaneous disease and has high response rates and good OS with doxorubicin-based combination chemotherapy.