Clinical application of SPECT-CT with 99mTc-Tektrotyd in bronchial and thymic neuroendocrine tumors (NETs)

Neuroendocrine tumors (NETs) of the thorax including bronchial and thymic tumors belong to foregut NETs. Limited loco-regional thoracic NETs can be resected with surgery, but in extensive metastatic disease the treatment is mainly palliative. A high incidence and density of somatostatin receptors (SSTR2, SSTR3, and SSTR5) are found in thoracic NETs. The purpose of this study was to evaluate the role of SPECT-CT somatostatin receptor scintigraphy (SRS) with 99mTc-Tektrotyd for imaging, staging and follow up of patients with bronchial and thymic neuroendocrine tumors. Forty-one patients with thoracic tumors with neuroendocrine differentiation were studied. Sixty-eight examinations including SPECT-CT studies of the neck and chest and/or abdomen and pelvis were carried out 2–4 hrs. post i.v. administration of aver­age 740 MBq activity dose of 99mTc-EDDA/HYNIC-TOC (Tektrotyd, Polatom). In all 41 investigated patients we obtained 81.25% (13/16), 88% (22/25) and 85.36% (35/41) of sensitivity, specificity and accuracy of this diagnostic approach, respectively. Somatostatin-receptor scintigraphy correctly identified all primary NETs located in the lungs and thymus. SPECT-CT studies with 99mTc-EDDA/HYNIC-TOC resulted in exact pre-surgical and pre-treatment N/M staging of bronchial and thymic NETs, except 2 cases with multiple hepatic metastases and 1 with massive suprarenal metastasis. It can be concluded that SPECT-CT with 99mTc-EDDA/HYNIC-TOC is a valuable tool for staging and follow-up of patients with thoracic NETs

A Rare Case of Primary Histiocytic Sarcoma of the Stomach

Histiocytic sarcoma is a rare lymphohematopoietic malignancy with aggressive clinical course and poor therapy response. The diagnosis relies on the confirmation of its histiocytic lineage and exclusion of other poorly differentiated tumors. Most of the cases present in extranodal sites, but primary gastric involvement is exceptional. We report a case of a 69-year-old woman with epigastric pain and systemic symptoms. Gastroscopy findings and biopsy report suggested a malignant neoplasm. The patient underwent distal subtotal gastrectomy with a 6-cm tumor in the body and antrum of the stomach and ten associated enlarged perigastric lymph nodes. Microscopically they were infiltrated with atypical tumor cells and immunohistochemical staining was positive for CD68, lysozyme, CD45, and CD4; 45% of the cells stained for Ki-67. The pathologic diagnosis was histiocytic sarcoma. CT body scans showed only enlarged retroperitoneal and abdominal lymph nodes. The patient received six cycles of CHOEP chemotherapy with complete therapeutic response, but three months later she experienced an aggressive systemic sarcoma recurrence and although salvage chemotherapy was initiated she died of progressive disease. The presented case widens the differential diagnosis of gastric malignancies, and emphasizes the significance of immunohistochemical examination for histiocytic sarcoma diagnosis. The collection and evaluation of cases of gastric histiocytic sarcoma are important to obtain further progress in prognosis and treatment