Follicular dendritic cell sarcoma (FDCS) is a rare neoplasm, located primarily in the germinal centers of primary and secondary lymphoid follicles of nodal and extranodal sites. It affected mainly young adults with median age of 40 years without gender predilection. Intra-abdomen as the only site of involvement of FDCS was a very uncommon condition and was associated with a particularly aggressive clinical course.[2,3]
2 Case presentation
A 19-year-old female visited the hospital emergency department for recent onset of upper abdominal pain. Physical examination indicated a firm mass in the upper part of the left side abdomen. The serum levels of amylase and lipase were elevated to 195 U/mL (normal range, 25–125 U/mL) and 1410 U/mL (normal range, 8–78 U/mL), respectively. Abdominal computed tomography (CT) scan showed a large tumor located in the left lobe lateral segment of the liver with compression to the pancreas and the stomach, and a smaller tumor at the small intestine (Fig. 1). Resection of both tumors was performed. Macroscopically, a mass sized 4.0 x 4.0 cm was seen in the mesentery of the ileum, 40 cm proximal to the ileocecal valve, and another tumor sized 12.6 x 8.3 cm in the liver lateral segment (Figs. 2 and 3). There was no tumor involvement over regional lymph nodes of the small intestine and liver or other parts of the abdomen. After operation, the serum levels of amylase and lipase returned to normal range (56 and 77 U/mL, respectively). Microscopical examination of the liver and mesentery tumors both showed FDCS, characterized by ovoid to spindle cells arranged in fascicles and whorls admixed with lymphocytes. Mitotic figures were frequently seen [>10/10 high-power field (HPF); Fig. 4]. Necrosis was also noted. The tumor cells showed immunoreactivity for follicular dendritic cell markers, including CD21 (Clone 2G9, Dilution 1:10; Leica, Germany), CD23 (Clone 1B12, Dilution 1:15; Leica, Germany), CD35 (Clone RLB25, Dilution 1:40; Sigma-Aldrich, Canada). In situ hybridization for Epstein–Barr virus (EBV) encoding small RNA (EBER; Inform EBER probe; Ventana Medical Systems, Tucson, AZ) failed to show positive cells (Fig. 4). A final diagnosis of small intestine FDCS with liver metastasis was made on these findings. Further staging workup showed no evidence of tumor involvement over other sites, including regional lymph nodes or bone marrow, and with no residual tumor over surgical sites. After the operation, patient received adjuvant chemotherapy for 3 months and there was no evidence of recurrence at 8-month follow-up.
FDCS was first presented by Monda et al in 1986. FDCS mainly affects peripheral lymph nodes, with the cervical nodes being the most common site. Other sites, including the mediastinal, retroperitoneal, and mesenteric areas lymph nodes, were extensively affected.[5,6] However, a wide variety of extranodal sites have been reported, including the tonsils, liver, spleen, oral cavity, gastrointestinal tract, bones, soft tissues, skin, and breasts. Clinical presentation of extranodal FDCS included abdominal pain, intestinal obstruction, rectal bleeding, and dyspepsia, when abdominal involvement was noted. Dyspnea, cough, dysphagia, and dizziness were reported when it comes to extra-abdominal involvement. Image study can be the initial tool for diagnosis of FDCS, and provides delineation of the extent of the mass and staging. Ultrasound and CT are usually the initial imaging modalities of choice used. CT can show smaller, relatively homogeneous masses; however, heterogeneity as a result of necrosis or hemorrhagic areas has been reported in more than 80% cases.
Univariate and multivariate analyses of FDCS prognostic factors was done by Saygin et al in 2013. Fifty cases of FDCS were collected and analyzed. Similar to other soft tissue sarcomas, large tumor size (≥6 cm), presence of coagulative necrosis, high mitotic count (≥5 per 10 HPFs), and significant cytologic atypia were shown to be associated with poor prognosis.
The current case demonstrated characteristic histopathological features of FDCS, including intimate admixture of oval to spindle-shaped tumor cells with mature lymphocytes and plasma cells. There are some unusual clinicopathological features as compared with those described in the literature. First, we present a case of intra-abdominal FDCS with mesentery and hepatic lesions present at the moment of diagnosis, with similar pathological result at both sites. Second, the tumors presented as acute abdominal pain with elevated serum amylase and lipase level, possibly due to the tumor mass located at the liver left lobe was large and with compression to the pancreas and stomach. Third, in our case, the tumor located at the ileum mesentery and liver both showed aggressive histopathological features, including marked nuclear pleomorphism, brisk mitotic rate that included occasionally atypical forms, nucleolar prominence, and coagulative necrosis.
With positive results of CD21, CD23, CD35, which are specific for FDCS, and classical features of morphology, the diagnosis of FDCS was made. According to the reports, almost all primary hepatic FDCSs were EBV-positive,[8,9] while our case was negative. In addition, it is very unusual for a large FDCS of liver origin with single site involvement of the mesentery and with sparing of other parts of the abdomen. Thus, we inferred that the primary site of the FDCS in our case is located at the intestine mesentery, and the liver lesion was considered consistent with blood-borne metastatic FDCS.
According to the study to date, the first-line treatment of localized FDCS is surgical resection, and there is still no consensus on performing optimal adjuvant chemotherapy and radiotherapy. Some treated FDCS with an aggressive lymphoma regimen, which often includes chemotherapy, whereas others treated FDS as a soft tissue sarcoma, with wide resection and adjuvant radiotherapy. Disseminated type of FDCS is suggested to use lymphoma-type chemotherapy, and the CHOP regimen including cyclophosphamide, adriamycin, vincristine, and prednisone is the most widely used.[10–12] In our presented case, adjuvant vinblastin chemotherapy is used and there is no evidence of recurrence for 8 months to date.
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. Chan JK, Fletcher CD, Nayler SJ, et al. Follicular dendritic cell sarcoma. Clinicopathologic analysis of 17 cases suggesting a malignant potential higher than currently recognized. Cancer 1997;79:294–313.
. Liberale G, Keriakos K, Azerad M, et al. Intraperitoneal follicular dendritic cell sarcoma: role of chemotherapy and bone marrow allotransplantation in locally advanced disease? Clin Med Insights Oncol 2015;9:9–13.
. Monda L, Warnke R, Rosai J. A primary lymph node malignancy with features suggestive of dendritic reticulum cell differentiation. A report of 4 cases. Am J Pathol 1986;122:562–72.
. Saygin C, Uzunaslan D, Ozguroglu M, et al. Dendritic cell sarcoma: a pooled analysis including 462 cases with presentation of our case series. Crit Rev Oncol Hematol 2013;88:253–71.
. Fonseca R, Yamakawa M, Nakamura S, et al. Follicular dendritic cell sarcoma and interdigitating reticulum cell sarcoma: a review. Am J Hematol 1998;59:161–7.
. Li J, Geng ZL, Xie CM, et al. Computed tomography imaging findings of abdominal follicular dendritic cell sarcoma: a report of 5 cases. Medicine (Baltimore) 2016;95:e2404.
. Martins PN, Reddy S, Martins AB, et al. Follicular dendritic cell sarcoma of the liver: unusual presentation of a rare tumor and literature review. Hepatobiliary Pancreatic Dis Int 2011;10:443–5.
. Lee CH, Yen YS, Shan YS, et al. Follicular dendritic cell tumor in liver: a case report and collective review. Gastroenterology Res 2010;3:139–43.
. Amiri-Kordestani L, Priebat D, Chia SH. Follicular dendritic cell sarcoma of the neck: case report and review of current diagnostic and management strategies. Ear Nose Throat J 2010;89:E14–7.
. Li L, Shi YH, Guo ZJ, et al. Clinicopathological features and prognosis assessment of extranodal follicular dendritic cell sarcoma. World J Gastroenterol 2010;16:2504–19.
. Ren R, Sun X, Staerkel G, et al. Fine-needle aspiration cytology of a liver metastasis of follicular dendritic cell sarcoma. Diagn Cytopathol 2005;32:38–43.