Follicular Dendritic Cell Sarcoma of the Esophagus - A Case Report

Follicular dendritic cell sarcoma (FDCS) is a rare neoplasm arising from the antigen-presenting cells of the B lymphocytes. Most of these tumors are known to occur in lymph nodes and to affect occasionally extranodal sites. However, FDCS in the gastrointestinal tract has been regarded as an extremely rare neoplasm. Herein, we report a case of primary FDCS originating from the esophagus in a 44-year-old man. The tumor was comprised of the oval to spindle-shaped cells in focal storiform arrangement admixing with lymphocytes. The tumor cells typically expressed positivity in CD21 and CD35.


Introduction
Follicular dendritic cells (FDCs) are located primarily in the germinal enters of secondary lymphoid organs and their function is to present antigens to specialized lymphocytes in cooperation with dendritic cells and Langerhans cells. Follicular dendritic cell sarcoma (FDCS) is a rare tumor arising from the antigen-presenting cells of the B-cell follicles of the lymph nodes [1]. Most FDCS arise within the lymph nodes (LNs). The incidence of FDCs is less than 0.1% of all lymphoid malignancy [2]. However, approximately 30% of FDCS have been reported to be located at extranodal sites including the tonsil, oral cavity, gastrointestinal tract, intra-abdominal soft tissue, and breast [3,4,5,6]. FDCS of the gastrointestinal tract is an extremely rare neoplasm with only 20 cases being reported. In the current study, we present our experience of FDCS arising from the esophagus in a 44-year-old man. The diagnosis is confirmed by immunohistochemistry. To our knowledge, ours is the second case of esophageal FDCS reported. Given the rarity of this tumor, additional experiences are needed for the further evaluation of the tumor's clinicopathologic features and the assessment of prognosis should be conferred.

Case report
The patient was a 44-year-old male who presented with foreign body sensation in the throat of a 3-month history. There was no history of vomiting, swallowing difficulty or bleeding in the oral cavity. Any palpable mass was not detected through physical examination. A chest CT scan showed a heterogeneous wall thickening at the distal esophagus. On preoperative endoscopy, the small ulcerative lesion was found in the esophagus and biopsy was diagnosed as squamous cell carcinoma (SQC). The patient was performed with Ivor-Lewis operation under general anesthesia for tumor removal.
On gross examination of the resected surgical specimen, two lesions were detected. An ulcerative lesion sized 3.5x1.8 cm was found 5cm away from the gastroesophageal junction. Another lesion found in the submucosal area sized 1.3x1.2 cm was located 6.5cm away from the gastroesophageal junction. After the operation, the foreign body sensation symptom was disappeared from the patients, but, the patient refused an additional chemo-radiation therapy and have not visited the hospital so far.

Discussion
FDCs present antigens to the B lymphocytes forming the network in the germinal centers of the lymph nodes [7]. The neoplasm derived from these cells are called FDCS which is very uncommon. Monda et al [8]. first described FDCS and Chan et al [3]. reported the first extranodal tumor. To date, less than 350 cases were reported [9].
So far, one case of esophageal follicular dendritic cell sarcoma has been reported [11]. The tumor was removed by endoscopic submucosal dissection. The patient initially refused additional chemoradiation therapy. After two years, the tumor recurred and later treated, but died during treatment. The case showed an aggressive clinical course. So it is believed that additional chemoradiation therapy will be needed after the surgery.
Unfortunately, our case is not known about the patient's clinical course after the surgery, it is difficult to include additional information on esophageal FDCS. Figure.1a. An ulcerative lesion (asterisk) is found at 5cm away from the gastroesophageal junction. Submucosal lesion (arrow) is located 6.5cm away from the gastroesophageal junction. showed a poor prognosis, whereas lesions arising in the lymph nodes behave as low-grade sarcoma with a relatively good prognosis [17]. No definite therapeutic approaches have demonstrated consistent efficacy [9].

Conclusion
I report the second case of primary FDCS originating in the esophagus.