Follicular lymphoma

Follicular lymphoma
ICD-O-1 Morphology
9692/3: Malignant lymphoma, centroblastic-centrocytic, follicular
Effective 1978 - 1991
ICD-O-2 Morphology
9690/3: Follicular lymphoma, NOS
Effective 1992 - 2000
ICD-O-3 Morphology
9690/3: Follicular lymphoma, NOS
Effective 2001 and later
for cases diagnosed 1978 and later
Primary Site(s)
See Module 7
Most common sites of involvement: lymph nodes, spleen, bone marrow (BM), peripheral blood (PB), and Waldeyer ring, skin, duodenum, ocular adnexa, breast and testis

See Abstractor Notes
Module Rule
Alternate Names
Diffuse follicular lymphoma, NOS
Extranodal follicular lymphoma
Follicular lymphoma, diffuse, NOS
Follicular lymphoma, NOS
Malignant lymphoma, centroblastic-centrocytic, follicular [OBS]
Malignant lymphoma, follicle center, follicular
Malignant lymphoma, follicular, NOS
Malignant lymphoma, lymphocytic, nodular, NOS [OBS]
Malignant lymphoma, nodular, NOS [OBS]
Other extranodal follicular lymphoma
Pediatric follicular lymphoma
Primary intestinal follicular lymphoma
B-cell malignancy of follicle center cells with at least partial follicular growth pattern, centrocyte (small cleaved cell) predominant with centroblasts (large non-cleaved cells) in minority. Neoplastic follicles closely packed and effacing nodal architecture, neoplastic cells with varying sclerosis between follicles. Primary cutaneous lymphomas of follicle (germinal) center cells are separately classified (see code 9597/3.)
Abstractor Notes
Follicular lymphoma, NOS histology is a generic disease description. DCO cases or path report only cases usually stay in this classification. The NOS histology may be the working diagnosis. Further review of the medical record should be done to look for the tests listed as definitive diagnosis.

The more specific follicular lymphomas are:
1. Follicular lymphoma, grade 1 (9695/3)
2. Follicular lymphoma, grade 2 (9691/3)
3. Follicular lymphoma, grade 3 (9698/3)

When a more specific diagnosis is identified, the histology should be changed to the more specific neoplasm name and code.

Most patients present with widespread disease, including peripheral and central (abdominal and thoracic) lymphadenopathy and splenomegaly. The BM is involved in 40-70%.

Only 1/3 of patients present with stage I or II at the time of diagnosis.

FL is graded according to the proportion of large cells (centroblasts). Studies suggest this histologic grading predicts clinical outcome, with more large cells behaving more aggressively and having a higher likelihood of transformation to diffuse large cell lymphoma.

When any area of diffuse large-B-cell lymphoma (DLBCL) is present in a FL the disease should be reported as diffuse large B-cell lymphoma (9680/3) (See PH rules).

There are three variants of FL:
1. Pediatric follicular lymphoma (mostly grade 3) involves cervical lymph nodes, other peripheral lymph nodes, or Waldeyer ring. Other extranodal involvement may occur. Children with FL typically have early stage disease. Pediatric FL lymphoma typically lacks BCL2 protein expression and t(14;18).

2. Primary intestinal follicular lymphoma in the GI tract occurs most commonly in the small intestine, and frequently involves the duodenum.

3. Duodenal follicular lymphoma is predominantly found in the second portion of the duodenum, presenting as multiple polyps. The diagnosis is most often an incidental finding. Most patients have localized disease and prognosis is excellent even without treatment.

Other extranodal follicular lymphomas occur in almost any extranodal site. Patients usually have localized extranodal disease and systemic relapses are rare. Testicular follicular FL are reported with increased frequency in children, but also are reported in adults.
Definitive Diagnostic Methods
Genetic testing
Histologic confirmation
Genetics Data
BCL2 gene rearrangements
Heavy and light chains rearranged
IGH(VD-J) gene rearrangement
Translocation t(14;18)(q32;q21)
Slg+ (IgM+/-IgD, IgG)
Hematologic Transplant and/or Endocrine Procedures
Radiation therapy
Transformations from
Corresponding ICD-9 Codes
202.0 Nodular lymphoma
Corresponding ICD-10 Codes
C82.9 Follicular non-Hodgkin's lymphoma, unspecified
Corresponding ICD-10-CM Codes (U.S. only)
C82.9 Follicular lymphoma, unspecified (effective October 01, 2015)
C82.5 Diffuse follicle center lymphoma (effective October 01, 2015)
C82.8 Other types of follicular lymphoma (effective October 01, 2015)
Signs and Symptoms
Drenching night sweats
Fever (for no known reason)
Lymphadenopathy (abdominal and thoracic)
Pain in chest, abdomen or bones (for no known reason)
Painless swelling in the lymph nodes in the neck, underarm, groin or stomach
Skin rash or itchy skin
Weight loss for no known reason
Diagnostic Exams
Progression and Transformation
25-35% of patients transform to DLBCL
Epidemiology and Mortality
Age: 60 years median age (rare occurrence under 20 years of age)
Incidence: Follicular lymphomas account for 20% of all lymhpomas
Sex: slight female predominance
Survival: 8-15 years median survival, closely related to the extent of the disease at diagnosis