Computer Tomography Imaging Findings of Abdominal Follicular Dendritic Cell Sarcoma: A Report of 5 Cases

Abstract

Follicular dendritic cell sarcoma (FDCS) is a neoplasm that arises from follicular dendritic cells. FDCSs originating in the abdomen are extremely rare. Clinically, they often mimic a wide variety of other abdominal tumors, and correct preoperative diagnosis is often a challenging task. To date, only scattered cases of abdominal FDCS have been reported and few data are available on their radiological features. Here we present the computer tomography imaging findings of 5 patients with surgically and pathologically demonstrated abdominal FDCS. An abdominal FDCS should be included in the differential diagnosis when single or multiple masses with relatively large size, well- or ill-defined borders, complex internal architecture with marked internal necrosis and/or focal calcification, and heterogeneous enhancement with "rapid wash-in and slow wash-out" or "progressive enhancement" enhancement patterns in the solid component are seen.

FIGURE 1

Case 1. FDCS arising from the mesentery in a 57-year-old woman. (A) The unenhanced CT imaging showed a large, well-defined heterogeneous mass (tumor 1) with patchy low-attenuating necrotic areas and coarse calcifications located centrally. (B–D) The enhanced multiphase CT images revealed marked heterogeneous enhancement with a “rapid wash-in and slow wash-out” pattern of enhancement in the solid component, accompanied by peritumoral serpentine draining veins. (E) Coronal reconstruction disclosed that there were multiple peritumoral lymph nodes (arrow), with some showing marked internal necrosis (white star). (F) Enhanced CT image showed multiple nodules in the right liver lobe with marked enhancement on arterial phase images (black arrow), which revealed distant metastasis. (G) After 4 months of follow-up, enhanced CT image showed the progression of hepatic metastasis. (H) The tumor was composed of spindle cells that were arranged in a fascicular pattern, and the spindle cells were admixed with lymphocytes (hematoxylin & eosin stain, ×200).

FIGURE 4

Case 4. FDCS arising from the left retroperitoneum in a 55-year-old woman. (A) The unenhanced CT imaging showed a large, well-defined heterogeneous mass with patchy low-attenuating areas located centrally (white star). (B–D) The enhanced multiphase CT images revealed moderate heterogeneous enhancement with a “rapid wash-in and slow wash-out” pattern of enhancement in the solid component and internal necrosis located centrally.

FIGURE 2

Case 2. FDCS with wide involvement of the mesentery and retroperitoneum in a 70-year-old man. (A) Unenhanced CT imaging showed a large, irregular, partially ill-defined mass (tumor 2) with intratumoral irregular necrosis (white star). (B–D) The enhanced multiphase CT images revealed a moderately heterogeneous tumor with a “rapid wash-in and slow wash-out” pattern of enhancement in the solid component, with serpentine vessels (white arrow) on arterial phase images, with the renal vessels of the left renal hilum encased (black arrow), widespread adjacent perirenal fascia and peritoneum involvement (white arrowheads), accompanied by renal vein and inferior vena cava thrombus (black arrowheads). (E) The sagittal reconstruction enhanced image also showed multiple peritumoral lymph nodes (short white arrows). Another mass (tumor 3) with marked internal necrosis located at the left retroperitoneum was also observed. (F) Lower abdominal enhanced CT image showed another oval, partially ill-defined mass (tumor 3) located at the left retroperitoneum with marked heterogeneous enhancement, marked internal necrosis (white star), and peritumoral lymph nodes (short white arrows).

FIGURE 3

Case 3. FDCS located in the right upper abdominal cavity in a 58-year-old woman. (A) The unenhanced CT imaging showed a partially ill-defined heterogeneous mass (tumor 4) located in patchy, low-attenuating areas with coarse and chunk-like calcifications. (B–D) The enhanced multiphase CT images revealed marked heterogeneous enhancement with a “rapid wash-in and slow wash-out” pattern of enhancement and internal necrosis (white star). (E) Coronal reconstruction found that the tumor was located near the duodenal bulb and shared an unclear boundary with it (white arrow). Peritumoral lymph node was observed (white arrowhead). (F) Enhanced CT image showed another oval, well-defined mass (tumor 5) located at the greater omentum with marked heterogeneous enhancement and internal necrosis (white star).

FIGURE 5

Case 5. FDCS arising from the mesentery in a 60-year-old woman. (A) The unenhanced CT imaging showed a lobulated, well-defined heterogeneous mass (tumor 7) with intratumoral coarse and chunk-like calcifications. (B–D) The enhanced multiphase CT images revealed moderate heterogeneous enhancement. The average density values of the solid component in the region of interest revealed a “progressive enhancement” pattern. (E–H) Middle abdominal CT image showed another oval, well-defined mass (tumor 8) located at the retroperitoneum with moderate heterogeneous enhancement. The average density values of the solid component in the region of interest revealed a “progressive enhancement” pattern.