This is a 73-year-old male patient with a biopsy proven invasive adenocarcinoma of the right colon who underwent imaging work-up before colectomy that shows 8 cm subhepatic cystic lesion in the right upper quadrant. During colectomy, the subhepatic lesion appears cystic and felt to arise from the left liver lobe. A right colectomy and removal of the liver lesion was performed and submitted to pathology. Section from the liver lesion is shown below.
Additional immunostains results: Cytokeratin AE1/E3 and CDX-2 are negative.
Final Diagnosis: Fibrin-associated Diffuse Large B-cell Lymphoma.
The H&E section displays a pseudocyst with a fibrotic wall, no lining epithelium, and few clusters of atypical lymphoid cells loosely embedded in a fibrinous amorphous pink material. The atypical cells are intermediate to large with frequent apoptotic bodies. Areas with cholesterol clefts, calcifications and necrosis are also noted within the cyst wall. On the periphery of the cyst there are benign looking lymphoplasmacytic aggregates. By immunostains, the atypical cells are positive for CD45 and CD20, and are negative for cytokeratin AE1/AE3, CD3, and CD138. The atypical cells are positive for EBV by in-situ hybridization. GMS, PAS-F, PAS-D and PAS stains are negative (not shown). Fibrin-associated diffuse large B-cell lymphoma is a B-cell lymphoma entity recognized by the WHO as an isolated and incidental lymphoma with a highly favorable clinical outcome, even with surgical excision alone However, Clinical correlation is needed to exclude the possibility of systemic disease.