Nephrotic syndrome as a possible indicator of colonic cancer: A case report

Abstract

The concept of paraneoplastic syndromes encompasses a spectrum of indirect clinical manifestations caused by secretion of bioactive products by malignant cells. Paraneoplastic glomerulopathy represent a distinct clinical entity where nephrotic syndrome can arise as a manifestation of underlying malignancies, particularly solid tumors. Membranous nephropathy is notably associated with such malignancies, highlighting the intricate relationship between nephrotic syndrome and cancer. The present study reports the case of a 44-year-old Caucasian male, smoker (22 pack-years) and chronic ethanol consumer who presented in the Emergency County Hospital of Craiova in March 2018 with abdominal distension, genital and leg edema and no prior medical history. Laboratory tests revealed inflammatory syndrome (erythrocyte sedimentation rate=110 mm/h, fibrinogen, 150 mg/dl, high levels of C reactive protein=6.87 mg/dl), as well as hypoproteinemia (total protein levels=3.90 g/l), hypertriglyceridemia=213 mg/dl, hypercholesterolemia=475 mg/dl, total urinary protein excretion of 12,500 mg/24 h and normal levels of urea (38 mg/dl) and creatinine (0.90 mg/dl). After meeting the diagnostic criteria for nephrotic syndrome (edema, proteinuria, hypoalbuminemia, and hyperlipidemia, it was investigated whether the syndrome was primary or secondary in origin. Notably, an unexplained inflammatory syndrome in conjunction with elevated tumor marker levels (carbohydrate antigen 19-9, 82.47 U/ml; Carcinoembryonic antigen-CEA=9.46 ng/ml) prompted a thorough imagistic investigation, using computer tomography. A polyp was discovered during colonoscopy, prompting a biopsy. The presence of adenocarcinoma was confirmed by histopathological analysis. The only clinical manifestation of the colonic malignancy was the symptomatic presentation of nephrotic syndrome, which led to early detection of the underlying cancer. Paraneoplastic nephropathy connects kidney disease with systemic cancer, showing that renal symptoms may aid in diagnosing hidden malignancies. Nephrotic syndrome, especially membranous nephropathy, is associated with various solid tumors. The present case demonstrated that paraneoplastic syndrome, though rare, may lead to early cancer detection. Ongoing research is essential for improving understanding, targeted therapy and patient management.

Keywords: colonic cancer; nephrotic syndrome; paraneoplastic syndrome.

Figure 1

Abdominal CT scan confirmed liver enlargement without pathological masses, a normal portal vein diameter, multiple mesenteric lymph nodes measuring up to 1.3 cm and increased renal echogenicity.

Figure 2

Pediculate polyp identified in inferior digestive endoscopy.

Figure 3

Histopathological examination revealed an adenomatous polyp with areas of moderately differentiated adenocarcinoma that did not involve the muscularis mucosae layer. Scale bar, 100 µm.

Figure 4

Moderately differentiated adenocarcinoma. Scale bar, 100 µm. Moderately differentiated adenocarcinoma was identified by histopathological examination of the biopsy samples.

Figure 5

Invasion of adenocarcinoma glands into the mucosa. Scale bar, 100 µm.

Figure 6

Optical microscopy of kidney biopsy showed thickened glomerular basement membrane due to immune complex deposition. Toluidine blue stained 1 µm-thick section. Scale bar, 100 µm.

Figure 7

Electron microscopy (1,000x magnification) of the kidney biopsy showed segmental sclerosis affecting ~25% of its structure, with thickened capillary loop walls. Rare interstitial foam cells and discrete lipid load were observed in tubular epithelia. Arteries and arterioles were normal and there was mild interstitial fibrosis without inflammation. Scale bar, 10 µm.