This clinical case illustrates complex interwoven medical, oncological and surgical pathological processes propelling this patient’s emergency admission. This patient’s extensive history and bona fide diagnosis of UC raised suspicion for an exacerbation of his disease or perhaps a benign or malignant neoplasm, however this presentation was due to a rare form of intussusception secondary to appendiceal LAMN. This highlights the clinical importance of ‘thinking outside the box’ when such patients present to the emergency room with a short history of severe abdominal symptoms.
Intussusception is an exceptionally rare finding in adult populations, typically mimicking other abdominal pathologies [3]. In adult patients, intussusception lead points are typically pathological in 90% of cases, 65% of which are neoplastic in nature [6]. Our case highlights these characteristics, in such that an ambiguous presentation was caused by LAMN and incidentally resected carefully at laparotomy. A favourable clinical outcome was achieved due to admitting physicians performing urgent endoscopy and subsequent CT scanning, leaving little option but to proceed to surgery. LAMN itself is rare diagnosis, and the natural history of the disease involves possible progression to pseudomyxoma peritonei (PMP) through the physiological redistribution phenomenon if left unresected [7, 8]. In this case, operating surgeons performed a meticulous resection of the appendiceal mass intraoperatively and consequentially prevented iatrogenic dissemination into the peritoneum. A 2018 case report from Burchard and colleagues reported a unique case of appendicular induced intussusception in an adult patient with UC [9], which was described by the authors as the sole documented case in medical and surgical literature. In light of this, we propose our adult presentation of intussusception with LAMN leading in the setting of UC as the second case of this nature currently documented. Furthermore, our review of the literature failed to yield results linking biologic therapies to incidence of LAMN or PMP or indeed to the incidence of intussusception, although the authors acknowledge this case describes dual pathologies in the setting of UC and biological therapy. Previous studies describe the benefit of chemotherapy in the setting of PMP, however the role of immunological therapies in LAMN/PMP is less well studied, and perhaps these therapies may potentiate the disease, as previously described with non-melanoma skin carcinoma and lymphoma [10,11,12].
Initially, our patient had a favourable clinical response to biological therapy prior to relapsing 12 weeks post-discharge from hospital. Recent hypotheses suggest that appendiceal tissue plays a role in the inflammatory and pathological processes driving symptomatic UC. In introducing the PASSION study, Sahami et al. postulate the appendix as a defective barrier which may alter the colonic microbiome, allowing aberrant interaction between bacteria penetrating the mucosa with innate immune cells. This potentiates abnormal immunological responses, which is thought to drive the pathophysiology of UC [13]. Rachmilewitz and Mizoguchi both proposed cytokine production by appendiceal tissue is responsible for triggering CD4+ T-cells in an immunological cascade in distal portions of the colon, causing symptoms in UC [14, 15]. These theories suggest that the anatomical and immunochemical properties of the appendix are somewhat responsible for distal inflammatory symptoms, and this patient’s remission in the immediate post-operative period would moderately support this. However, the relapse of his symptoms after 12 weeks suggests the multifactorial nature of UC with involvement of immune processes outside of the appendix and proposes appendicectomy will not prove beneficial in controlling the symptoms associated with this patient’s UC. The authors acknowledge novel theories regarding immunological crosstalk between the appendix and colonic tissue in diseases processes like UC, however we wish to emphasise the clinical the value of urgent evaluation using laboratory, endoscopic and radiological investigations in emergency cases as described.
