Teaching cases

Case presentation: Male. 74 y.o. Rectal carcinoma. CT scan of abdomen and pelvis revealed a mass with an exophytic component on the left posterolateral segment of the rectum, and a small adjacent lymphadenopathy of 1 cm. A chest radiograph showed left pleural effusion and an increase in the image of basal atelectatic condensation that existed in a study from the previous year. The surgery was performed the following month, with an ileostomy. The biopsy showed an ulcerated rectal lesion of 7 x 8 x 3 cm, tubular histological type with mucinous-focal component with lymphatic permeation, infiltrative histological margin and without blood permeation, perineural or tumour perforation, 2/3 positive lymph nodes. Conclusion: Dukes C colon carcinoma Group C2 by Astlery Coller, Group III by Jass. Teaching points: PET-FDG can be used for initial staging and re-staging in rectal carcinoma. PET-FDG can help clarify the origin of new CT findings.

Case presentation: Male 74 y.o. Seventy-four year old man with history of rectal carcinoma. Receives neoadjuvant chemo-radiotherapy (QT/RT) before surgery. CT examination of abdomen and pelvis showed a mass with exofitic component in left postero-lateral aspect of rectum and a small adjacent lymph node (1 cm). Chest-Rx showed increased left pleural effusion and basal atelectasia already observed a year before. The patient is operated the following month, being with ileosthomy thereafter. Pathology showed rectal ulcerative lesion 7x8x3 cm corresponding to a carcinoma of tubular type with mucinous focal component, lymphatic invasion, infiltrative margin and no evidence of blood vessel invasion, with 2/3 positive lymph nodes. Conclusion: colon Ca - Dukes C Group C2 (Astler & Coller), Group III (Jass). (More clinical history in the cases) Teaching points: PET-FDG can be used for initial staging and restaging in rectal carcinoma. PET-FDG can help clarify the origin of new CT findings.

Case presentation: Male. 25 y.o. Clinical background: intermittent fever in the preceding 4 months, non quantitated weight loss and night sweats. Physical examination was unremarkable, except for hepatosplenomegaly. Initial lab test results: microcytic hypochromic anaemia (otherwise unremarkable). CT scan: bilaterally enlarged neck lymph nodes. Neck lymph node biopsy: negative. Teaching points: There is a role for scintigraphy with gallium-67 citrate in patients with FUO, particularly if PET CT is unavailable. High quality images should be obtained: SPECT is mandatory. A positive gallium-67 scan can serve as guidance for the diagnostic biopsy as it will point out the most active lesions. SPECT CT obtained with hybrid gammacameras or by software fusion imaging can be useful for better lesion targeting. Gallium-67 citrate allows upfront whole body scanning which is useful, particularly in patients with lymphoma. This case illustrates the concept of tumor heterogeneity where certain tumor areas disclose different levels of gallium-67 avidity.

Case presentation: Female. 50 y.o. Was diagnosed with a right paravertebral pulmonary mass obstructing the inlet to the middle lobe. Surgical treatment: resection of middle lobe and right inferior lobe. Upon sectioning the right intermediate bronchus a mechanical suture was used to close the stump. Final diagnosis: non-functioning well-differentiated bronchial neuroendocrine tumor. Teaching points: To adequately determine that a localization result is false positive or true positive requires either direct examination (by surgery, cytology or biopsy), other imaging studies to clarify the lesion or extensive follow up and careful comparison to the clinical context to determine the true nature of the lesion.

Case presentaion: Male. 50 y.o. Diagnosed with a non hormone-producing, well-differentiated neuroendocrine tumor of the small intestine. A wide resection of the small intestine was practiced. Intraoperative examination of the gut did not disclose any other tumors in the intestinal mucosa. The patient recovered well and remained asymptomatic. ?One year after the surgery his cancer surgeon ordered an abdomial CT scan that was inhterpreted as unremarkable. Three months later he was also examined by this cancer endocrinologists whom in turn also decide to order a somatosin receptor scintigraphy. Teaching points: SPECT should be a customary practice in cancer centers, either when using cancer tracer (e.g., In-111 or Tc-99m octreotide, I-131 sodium iodide, I-131 MIBG, Ga-67 citrate, Tc-99m(V) DMSA, Tc-99m MIBI) or not (e.g., Tc-99m MDP). In recognition of the incremental value of image fusion, Nuclear Medicne technologists should always consider the potential medical necessity to retrospectively fuse non-concurrently obtained SPECT and CT or MR images. Nuclear Medicine technologists should always follow a rigorous protocol to facilitate future image coregistration, including careful and reproducible patien positioning and using (radio-opaque and radioactive) external markers in a routinely fashion for every SPECT acquisition.

Case presentation: Female. 82 y.o. Complaint:gastritis. Upper endoscopy findings: Micronodular mucosa in gastric fundus with multiple 1-mm lesions. 3 lessions > 1mm were resected. Anatomopathology results: Diffuse chronic atrophic gastritis. Focal intestinal metaplasia with no dysplasia.Neuro endocrine micronodular hyperplasia. Type-1 neuroendocrine tumor suspected. The patient refused surgical antrectomy. A somatostatin receptor scintigraphy was ordered to identify a gastrinoma and to rule out a gastric carcinoid. Teaching points: In type 1 gastric carcinoids, diminution of parietal cell function (eg. autoimmune destruction in pernicious anaemia or atrophic gastritis) reduce luminal acidity, which stimulates gastrin secretion and prolonged hypergastrinemia, culminatinf in ECL cell proliferation through phases of hyperplasia, dysplasia and neoplasia. Gastric carcinoids are of increasingf clinical conCern because they may develop hypergastrinemic state. However, they are difficult to diagnose. Somatostatin receptor scintigraphy is a reasonably sensitive and highly specific imaging modality to localize gastric carcinoids in patients with hypergastrinemic states. No abnormal uptake was seen in the gastric fundus, therefore we can confidently rule out a gastric carcinoid. We can only speculate that the focal uptake in the gastric antrum was a false poisitve result induced by G cell hyperplasia. Antrectomy is no longer considered a useful treatment because the antrum only produces 60% of the body gastrin, whereas the duodenum can produce the remaining 40%.

Case presentation: Female. 45 y.o. -Right hip pain durin exercise. History of resected melanoma 2 years before. Plain X rays of pelvis and right limb were normal. Since pain persited, a CT scan was ordered. Teaching points: PET/CT is indicated for staging and re-staging of melanoma. The technique has high sensitivity for detecting bone marrow involvement. Although conventional bone scanning is sueful, PET/CT has the power of detecting also soft tissue involvement (in this case, however, the thyroid finding does not add to the prognosis). Thyroid metastases from melanoma are no frequent. One paper reports on 5 incidental findings of thyroid metastases with FDG: 2 from melanoma, 2 from colotrectal cancer, 1 from gastric cancer. ?Primary malignant thyroid carcinoma, especially papillary type, also take up FDG.