Lymphomas are the third most common childhood cancers of which 60% are Non - Hodgkin's lymphoma.

Q: What is Non - hodgkin's lymphoma
(NHL)?

A: It results from malignant proliferation of cells of lymphocytic or histiocytic origin. It is generally restricted to the spleen and the lymph nodes.

Q: What are its clinical features & presentation?

A: NHL occurs most commonly in the second decade of life with a male preponderance of 3:1. It is less frequent in children less than 3 years of age. NHL is the most common malignancy in patients with AIDS. Hence, all patients with HIV +ve results should be screened for NHL.

The clinical features of NHL are varied and depend on location, extent and histology of the tumor. Children with NHL usually present with extranodal disease involving the mediastinum (superior vena cava syndrome), abdomen - in the ileocecal, appendical, colonic or retroperitoneal region (abdominal pain, vomiting, palpable mass, intussusception, ascitis, hepatosplenonmegaly etc) and head & neck region (cervical adenopathy, parotid involvement, jaw and tonsillar swelling). Endemic Burkitt's lymphoma presents as a jaw mass in 50% of the cases.

Q: How is Non - Hodgkin's lymphoma diagnosed ?

A: Biopsy of the involved lymph node is the most important diagnostic criteria. The biopsy material should be evaluated for histological subtype to determine the therapy and prognosis. NHL in children spreads rapidly, hence urgent diagnosis is essential. Staging of the disease is also required to determine the therapy. As in Hodgkin's disease, a pathologic staging of the disease is not indicated. Staging is based on a combination of history, physical examination, X Ray (including CT Scan of chest, abdomen and pelvis, if indicated), gallium scan, bone marrow aspiration and biopsy and biochemical profile. In patients with mediastinal mass, if pleural effusion is present, a thoracocentesis should be done as cytological diagnosis is possible.

Q: How do you stage NHL?

A: Staging system for childhood NHL:

Murphy classification.

Stage I	-	A single tumor or nodal area outside of the abdomen or mediastinum.
Stage II	-	A single tumor with regional node involvement.
		Or
		Two or more tumors or nodal areas on one side of diaphragm.
		Or
		A primary gastrointestinal tract tumor (resected) with or without regional node involvement.
Stage III	-	Tumors or lymph nodes on body sides of diaphragm
		Or
		Any primary intrathoracic or extensive intra abdominal disease
		Or
		Any paraspinal or epidural tumors.
Stage IV	-	Patients with bone marrow= or CNS* disease regardless of other sites of involvement.

= Bone marrow involvement is defined as > 5% but < 25% replacement of marrow elements by malignant cells without tumor involvement.

*CNS involvement is defined as WBC greater than 5/microliter in CSF with malignant cells.

The most important prognostic factor is the extent of the disease as determined by pretreatment staging. Patients with stage I & II diseases have excellent prognosis with 5 year survival rate of approximately 90%.