Follicular lymphoma, grade 2

Follicular lymphoma, grade 2
ICD-O-2 Morphology
9691/3: Follicular lymphoma, grade 2
Effective 1992 - 2000
ICD-O-3 Morphology
9691/3: Follicular lymphoma, grade 2
Effective 2001 and later
for cases diagnosed 1992 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 adnex, breast and testis

See Abstractor Notes
Module Rule
Alternate Names
Diffuse, follicular lymphoma, grade 2
Follicular lymphoma, diffuse, grade 2
Follicular lymphoma, grade 1-2
Follicular lymphoma, low grade
Grade 2, follicular lymphoma, diffuse
Malignant lymphoma, mixed cell type, follicular [OBS]
Malignant lymphoma, mixed cell type, nodular [OBS]
Malignant lymphoma, mixed lymphocytic-histiocytic, nodular [OBS]
Malignant lymphoma, mixed small cleaved/large cell, follicular [OBS]
A neoplasm of follicle centre B cells (centrocytes/cleaved follicle centre cells (FCC) and centroblasts/noncleaved FCC) which has at least a partially follicular pattern
6-15 centroblasts/hpf
Abstractor Notes
Code follicular lymphoma, grade 2, when there is a grade such as 1-2. Assign the histology code of the higher grade (9691/3), even though the grade 1 histology code (9695/3) is numerically higher.

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
Chromosomal translocations T(11;18)
IGH(VD-J) gene rearrangement
Immunoglobin heavy and light chain genes rearranged
Translocation t(14;18)(q32;q21)
Heavy and light chains rearranged; t(14;18)(q32:q21)-85% with rearrangement of Bcl-2 gene
Tumor cells Sig+(IgM+/-, IgD, IgG)
Stem cell transplant
Transformations from
Corresponding ICD-9 Codes
202.0 Nodular lymphoma
Corresponding ICD-10 Codes
C82.1 Mixed small cleaved and large cell follicular
Corresponding ICD-10-CM Codes (U.S. only)
C82.1 Follicular lymphoma grade II (effective October 01, 2015)
Signs and Symptoms
Drenching night sweats
Fever (or 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
Cytogenetics studies
CT (CAT) scan
Laparoscopy (rarely performed)
Laparotomy (rarely performed)
MRI (Magnetic resonance imaging)
PET scan (positron emission tomography scan)
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