“Early Lesion” of Follicular Lymphoma (FL) Precedes Clinically Overt FL: A Retrospective Study of Lymph Nodes (LNs) Obtained At Surgery with LNs Dissection for Preceding Cancer.

Abstract

AbstractAbstract 2716Follicular lymphoma (FL) is the most common subtype of indolent lymphoma and most patients with FL are diagnosed with advanced stage. “Early lesion” of FL including partial involvement of FL and FL in situ was proposed recently, of which clinical implication remains uncertain. One report suggested that some patients with FL in situ can develop into clinically overt FL afterward (Blood 2011; 118:2976). However, it is unclear whether clinically overt FL is usually preceded by “early lesion”. In order to answer this question, we retrospectively reviewed the archived pathological specimen of lymph nodes (LNs) that had been obtained at surgery with LNs dissection for a preceding other malignancy before the diagnosis of FL in patients with clinically overt FL. Materials and MethodsCases for study were diagnosed as FL at Toranomon Hospital between January 2001 and March 2012 and had undergone surgery with LNs dissection for a preceding malignancy. We reexamined the dissected LNs by morphology and immunohistochemistry. The hematoxylin and eosin stained slides were reviewed and immunohistochemical staining was performed using a streptavidin-biotin complex technique. Antibodies included the following: CD5, CD10, CD20, CD21, BCL2, BCL6, MIB1. This study was performed with the approval by the Institutional Review Board. ResultsAmong the 167 patients who were diagnosed as FL at Toranomon Hospital during this period, 8 patients (4.8%) had undergone surgery with LNs dissection for a preceding malignancy (Table). Preceding malignancy was gastric carcinoma (n=3), esophageal carcinoma (n=2), and endometrial carcinoma (n=2), and colon cancer (n=1), respectively. Surgery for preceding malignancy had been performed at a median of 18 months (9–186 months) before the diagnosis of FL. No patient had lesions suggestive of lymphoma on preoperative imaging studies or endoscopic examinations. With immunostaining of the archived specimen, FL was found in all of the 8 cases, of which 6 cases were FL in situ and 2 cases were usual FL. The number of resected LN was median 38 (19–153) and the involvement of FL was detected in 60% of the resected LNs. LNs metastasis of carcinoma was found in 4 cases. Median duration from surgery for precedent malignancy to the diagnosis of overt FL was 26 mo(12–186) in patients preceded by the FL in situ and 13 mo (9,17) in patients preceded by clinically latent but pathologically usual FL. ConclusionWe found that FL is preceded by latent FL that is only detectable by pathology. Remarkably, 6 out of 8 cases were preceded by FL in situ. This retrospective series suggests that “early lesion” of FL is a precursor lesion of clinically overt FL.TableCaseAge at FL diagnosisFL involved LNs at FL diagnosisExtranodal lesionBone marrow involvementSite of preceding cancerMonth between surgery to FL diagnosisFL state at dissected LNsNumber of dissected LNsNumber of FL involvement LNsNumber of cancer metastasis LNs160paraaorta, mesentery1stomach9Grade 134243263paraaorta, mesentery0esophagus46in situ153411350duodenum0stomach12in situ59530465paraarota, mesentery0esophagus33in situ70371573mesentery0colon19in situ1950646paraarota, inguinal0uterine corpus17Grade 242420768duodenum1stomach13in situ251310873inguinal, paraarota, mesentery1uterine corpus186in situ32300 Disclosures:No relevant conflicts of interest to declare.