Poster - #2022SPHU-14 - Keywords: Omental Cake

C 12: Omental Cake: An Enigma!

Amogh Pathak, MD
Saint Peter’s University Hospital – Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey

ABSTRACT:
Omental Cake: An Unsolved Enigma Greater omentum plays a unique role in the intraperitoneal pathology by functioning as a component of immune system. Any inflammatory, infectious or neoplastic process can lead to diffuse thickening of the omentum. Radiologically, the omentum takes form of a band which transforms to a mass that displaces bowel from abdominal wall. This is described in radiology as omental cake. Common pathologies causing omental caking are abdominal tuberculosis and malignancies (1). While ovarian malignancies are most common causes, gastric, pancreatic, and colonic cancers are other common malignancies associated with omental spread. Virtually any tumor capable of intraperitoneal spread (2). Case: This is an unusual case of 51-year-old Indian male with Stage I renal cell carcinoma with a coincidental finding of unrelated omental caking, which lead to exploration of possible underlying etiology of the peritoneal changes. In this particular case the principle of Occam’s razor was not followed. Patient presented with partial small bowel obstruction and abdominal distension. He underwent CT scan that revealed ascites, 4.7 cm renal lesion and omental caking. Primary thought was peritoneal carcinomatosis. As the renal mass was confined to kidney (stage I, without spread to fascia or vessels), it was excised and biopsy revealed papillary type of renal cell carcinoma. Presence of omental caking was not explained by Stage I renal cell carcinoma. To further evaluate the omental caking, patient underwent esophago-gastro-duodenoscopy and colonoscopy with normal findings except hemorrhoids. Peritoneal fluid had no malignant cells. Biopsy of the mass revealed non-caseating granulomatous inflammation with reactive mesothelial cells. QuantiFERON gold and ascitic fluid adenosine deaminase was negative. Angiotensin converting enzyme levels were low. Patient had a questionable erythema nodosum in past. He also had low ANA (anti-nuclear antibody) and PR-3 (Proteinase-3) antibody positive. Discussion: Differentials for non-caseating granulomatous inflammation forming omental caking were tuberculosis (TB) v/s sarcoidosis v/s peritoneal carcinomatosis. No evidence for TB was found on biopsy and serological testing. Initial ascites resolved after nephrectomy; hence it could be a reactive ascites. Patient had no malignant cells in the omental biopsy and lymph node biopsy. The findings of omental caking still remain unexplained. Plan for patient is to further undergo a repeat omental biopsy to search for evidence of acid-fast bacilli. Purpose of this abstract is to discuss top differential for omental caking. It will also showcase an approach taken to evaluate and investigate for its underlying etiologies. References: 1. Hamrick-Turner JE, Chiechi MV, Abbitt PL, Ros PR. Neoplastic and inflammatory processes of the peritoneum, omentum, and mesentery: diagnosis with CT. Radiographics. 1992 Nov;12(6):1051-68. doi: 10.1148/radiographics.12.6.1439011. PMID: 1439011. 2. Mamlouk MD, Vansonnenberg E, Shankar S, Silverman SG. Omental cakes: unusual aetiologies and CT appearances. Insights Imaging. 2011 Aug;2(4):399-408. doi: 10.1007/s13244-011-0105-4. Epub 2011 May 22. PMID: 22347961; PMCID: PMC3259316.