Thymic carcinoid in the pancreas: metastatic disease or new primary tumours

Pancreatic metastasis resulting from thymic neuroendocrine carcinoma: A case report

Thymic neuroendocrine carcinoma (NEC) is a rare type of cancer. Unlike other thymic epithelial tumors and carcinoids originating in other locations, thymic NEC possesses a more aggressive biological behavior, including invasion to proximal structures, local recurrence and distant hematogenous metastasis. Distant metastasis is often observed in the bones, lungs, spleen, liver and adrenal glands. However, pancreatic metastasis resulting from thymic NEC is extremely uncommon, and only a few cases of patients with this disease have been reported. The current study presents the case of a patient with pancreatic metastasis resulting from thymic NEC. The patient was admitted to hospital with an anterior mediastinal neoplasm, which was identified using chest enhanced computed tomography. The patient underwent a monobloc excision of the tumor with resection of involved structures. Subsequently, a pathological diagnosis of atypical thymic carcinoid was provided, according to the morphological characteristics observed and the expression of neuroendocrine markers, as identified by immunohistochemistry. Following surgery, the patient received adjuvant chemotherapy and radiotherapy. However, ~2 years after surgery, metastasis at the pancreatic head was identified. The patient underwent a total pancreatectomy and splenectomy, and did not receive any post-operative therapies; however, the patient succumbed to the disease 9 months following surgery. Overall, the results from the present study demonstrate the clinical features of thymic NEC, which may aid with the diagnosis of this rare disease in other patients.

Usual and unusual neuroendocrine tumor metastases on (68)Ga-DOTANOC PET/CT: a pictorial review

Neuroendocrine tumors (NETs) are slow-growing indolent tumors that often present with metastatic disease at the outset. They commonly metastasize to lymph nodes, liver, bone, and lungs. However, metastasis to other rare sites may occur. It is important to have clear knowledge of unusual NET metastatic sites because their presence may lead to a more directed investigation. Also, it will be helpful in ruling out incidental second malignancies that might be encountered. The objective of this pictorial article was to provide an illustrative tutorial showing the clinical utility of Ga-labeled somatostatin analog [1, 4, 7, 10-tetraazacyclododecane-1, 4, 7, 10-tetraacetic acid]-1-NaI3-octreotide (Ga-DOTANOC) PET/CT for imaging usual and unusual metastatic sites in patients with NETs.

Prospective study of thymic carcinoids in patients with multiple endocrine neoplasia type 1

Little is known of the natural history of thymic carcinoids in multiple endocrine neoplasia type 1 (MEN1). This is important because in 1993 they were identified as a frequent cause of death, yet only small retrospective studies and case reports exist. We report results of a prospective study of 85 patients with MEN1 evaluated for pancreatic endocrine tumors and followed over a mean of 8 yr with serial chest computed tomography, magnetic resonance imaging (MRI), chest x-ray, and, since 1994, octreoscans [somatostatin receptor scintigraphy (SRS)]. Seven patients (8%) developed thymic carcinoids. Patients with and without carcinoids did not differ in clinical, laboratory, or MEN1 tumor features, except for male gender and the presence of a gastric carcinoid. All thymic tumors were hormonally inactive. Four thymic carcinoids lacked 11q loss of heterozygosity, although it was found in three pancreatic endocrine tumors. Computed tomography and/or MRI were more sensitive than SRS or chest x-ray in detecting tumors initially or with recurrence. All patients underwent resection of the thymic carcinoid, and in all patients followed more than 1 yr, the tumor recurred. Bone metastases developed in two patients and were detected early only on MRI, not SRS. This study provides information on early thymic carcinoids and allows modifications of existing guidelines to be recommended for their diagnosis, surveillance, and treatment.

Primary neuroendocrine tumors of the thymus

Primary neuroendocrine tumors of the thymus are highly aggressive tumors that rarely occur. A little more than 200 cases have been reported, many of which were single case reports. Only a few articles contained modest series from single centers for analysis. A review of 157 cases collected from the major series reported to-date show a clinical pattern with male preponderance (male:female ratio, 3:1) and a mean age of 54 years. Most patients presented with symptoms and signs of local compression. Almost 50% of these tumors were functionally active and were associated with endocrinopathies. Several histologic variants have been described, all with similar ultrastructural features. The biologic behavior of these tumors shows a direct relation to the degree of differentiation. Whenever possible, surgical resection is the treatment of choice as adjuvant therapy is controversial and has been used with variable success. Potential therapies exploit the presence of somatostatin receptors on a variety of these tumors. Use of radiolabeled Octreotide for radionuclide therapy has yielded tumor inhibition in animal models and may have clinical application. Fifty-one percent of the patients survived 3 years, 27% survived 5 years, and less than 10% survived beyond 10 years. Histologic grade, tumor extension, and early detection are the most important factors affecting survival. Other prognostic factors that impact outcome include presence of endocrinopathy, incomplete resectability, nodal status, and presence of distant metastasis.