A 71-year-old man complained of a two week history of right-sided abdominal pain that started after he began his first round of chemotherapy with R-CHOP with pegfilgrastim for mantle cell lymphoma. He presented to the emergency department (ED) after he developed severe (9 out of 10) right lower quadrant abdominal pain, approximately 17 days after starting chemotherapy. A physical examination in the ED revealed tenderness most pronounced in the right lower quadrant, with guarding and rebound pain. Lymphadenopathy was also noted in the cervical and supraclavicular regions. Imaging by CT scan of the abdomen/pelvis revealed an enlarged appendix with disruption of the appendiceal wall and small foci of gas and fluid consistent with a contained perforation. No associated mass or tumor was observed in the imaging studies. Peripheral blood was collected and sent for complete blood count, which demonstrated a normocytic anemia with a relative neutrophilia.
The patient's mantle cell lymphoma had been recently diagnosed on the basis of involvement of bone marrow and cervical lymph nodes. Imaging studies revealed widespread lymphadenopathy and splenomegaly. The mantle cell lymphoma expressed CD5 and kappa light chain restriction by flow cytometry and expressed Cyclin D1 by immunohistochemistry. The mantle cell lymphoma was noted to have a high Ki-67-defined proliferative rate of 60–80%, a finding that suggested an aggressive clinical behavior. There was no prior documented involvement of the gastrointestinal system. Based on these findings, the patient was diagnosed with an aggressive mantle cell lymphoma, stage IVA. The treatment plan for the lymphoma included 6 cycles of R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) chemotherapy with pegfilgrastim support for induction, which was to be followed by high-dose consolidation and stem cell collection (mobilized, peripherally collected) in anticipation of potential future autologous bone marrow transplantation.
Several days before the patient was to receive the second cycle of R-CHOP; however, he presented with acute appendicitis and was referred urgently to general surgery. He was taken to the operating room on the same day for laparoscopic appendectomy, which was converted to open appendectomy with washout when it was directly observed that the appendix had perforated and had dense adhesions. Two small abscess cavities were identified, each of which drained purulent material on opening. His recovery from surgery was generally unremarkable other than mildly prolonged postoperative ileus and the presence of two small persistent abscesses by imaging postoperatively. He was discharged 9 days after his surgery on antibiotics and was continued on rituximab alone until he was able to return to his second cycle of CHOP roughly 1 month after his presentation with acute appendicitis.
The gross examination of the appendectomy specimen showed an enlarged appendix with a clear area of perforation and fibrous adhesions on the serosal surface. Representative sections were submitted for conventional histologic processing. While some portions of the appendiceal lumen had normal histologic findings, the most inflamed portions had a disrupted mucosal surface (). Scattered on the mucosal surface were small aggregates composed predominantly of small lymphocytes and few plasma cells, along with focal neutrophil-rich areas consistent with suppurative inflammation (Figures and ). The appendiceal wall was thickened and fibrous (Figures and ), and the inflamed serosa contained dilated vessels with a surface coated by fibrinopurulent debris (). Overall, the submucosal lymphoid aggregates appeared small (). They did not have discrete germinal centers and were composed predominantly of small- to intermediate-sized lymphocytes with high nuclear: cytoplasmic ratios, but without significant nuclear atypia. As the patient had a history of mantle cell lymphoma, we performed immunohistochemical studies on the lymphoid aggregates (). The lymphoid aggregates contained predominantly CD20-positive B cells () in association with CD3-positive T cells, which were interspersed and predominantly at one edge (not shown). The neoplastic B cells expressed nuclear cyclin D1 gene product (), but lacked expression of BCL-6 (not shown). The morphologic and immunophenotypic findings confirm that the patient's appendiceal specimen was involved by mantle cell lymphoma.
Figure 1 (a) Cross-section of appendix with disrupted mucosal surface and small lymphoid aggregates (hematoxylin and eosin, 2x objectives); (b) serosal surface of appendix with fibrinopurulent adhesions and dilated vessels (hematoxylin and eosin, 10x objective); (more ...)
Unfortunately, while the patient recovered postoperatively, in the interim he developed circulating neoplastic lymphocytes in the peripheral blood. His mantle cell lymphoma proved to be refractory to multiple chemotherapeutic regimens. He became increasingly ill and, in discussion with his family, care was ultimately withdrawn. The patient died from his lymphoma approximately 6 months after his presentation with acute appendicitis.