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Objective: To compare the usefulness of MRI and PET/CT in nodal staging (N) of patients with locally advanced rectal cancer (LARC)., Material and Methods: Retrospective study of patients with LARC, who completed their initial staging with PET/CT, between January-20 and March-23. Regional nodes were assessed, and N was determined using both techniques according to TNM criteria. Concordance between MRI and PET/CT was analyzed. The accuracy of both techniques was calculated for those patients who underwent direct surgery. Non-regional pelvic lymph nodes were evaluated by both modalities., Results: Among the 73 patients, 48 were ultimately diagnosed with a locally advanced stage. Of these, 39 underwent neoadjuvant treatment (chemoradiotherapy) followed by surgery, and 9 direct surgery. In 25, the PET/CT extension study revealed distant disease, leading to systemic treatment. Weak concordance was observed between MRI and PET/CT in determining N (k=0.286; p<0.005). Out of 73 patients, 31(42%) exhibited concordance, and 42(58%) showed discordance. In 83% of the discordant cases, MRI overstaged compared to PET/CT, with 17 cases indicating nodal involvement (N+) by MRI and N0 by PET/CT. Diagnostic accuracy was 78% for both techniques. Sensitivity, specificity, positive predictive value, and negative predictive value were 80%, 75%, 80%, and 75% for MRI, and 60%, 100%, 100%, and 67%, for PET/CT. PET/CT identified pelvic metastatic adenopathies in 8 patients that were not visible/doubtful by MRI., Conclusions: In the initial nodal staging of rectal cancer MRI overstages relative to PET/CT. Both modalities are complementary, PET/CT offers higher specificity and MRI higher sensitivity., (Copyright © 2024 Sociedad Española de Medicina Nuclear e Imagen Molecular. Published by Elsevier España, S.L.U. All rights reserved.)

We present a patient with previous history of neuroendocrine tumour in the head of the pancreas, well differentiated and treated surgically. Two years later, there was suspicion of relapse. An endoscopy, CT scan and 111In-pentetreotide scintigraphy were performed. The 4 hour image showed two uptake lesions in the liver and the peripancreatic region. However, these focal uptakes had disappeared in the 24 hour image. In view of this result, a PET-FDG scan was carried out, showing two hypermetabolic lesions. The biodistribution of 111In-pentetreotide may be influenced by various parameters, including the time of scanning, and may show neuroendocrine tumours without somatostatin receptors in relapses. PET-FDG is an interesting tool to help characterise these cases.

Tumours that produce metastases in the paranasal sinuses or sphenoidal sinus are rare; the carcinomas of kidney and lung being the most frequent with this type of metastasis. Distant metastases from differentiated thyroid carcinoma are rare and, moreover, when they metastasize, they do so into lung and bone. We report a patient who had a papillary thyroid carcinoma with metastases into the sphenoidal sinus.

A common cause of the Cushing's Syndrome (CS) is nodular suprarenal hyperplasia (NSH), which is characterized by the presence of nodes in both suprarenal glands. Its pathophysiology is not well known and its diagnosis is quite difficult due to the heterogenicity of the biochemical and radiological data. We analyzed the suprarenal gammagraphies (SRG) of 7 patients with anatomopathological diagnosis of NSH. Bilateral uptake was observed in all cases and in five patients, such bilateral uptake presented a clear asymmetry. We believe that these observations demonstrate a bilateral suprarenal affectation and are of great use in order to orientate the diagnosis of NSH and, especially, in order to differentiate it from other suprarenal diseases causing CS, like adenomas, in which uptake is unilateral.