Primary Thyroid Lymphoma: A Retrospective-Observational Study in a Single Institutional Center.

Background and Objectives: primary thyroid lymphoma (PTL) is a rare neoplasm, displaying a variety of histological features. It is often a challenge for pathologists to diagnose this tumor. Materials and Methods: this study is a retrospective analysis of clinical and pathological characteristics of a group of eleven patients (eight women and three men, mean age 68 years, range 50-80 years) diagnosed with PTL. Results: nine patients (81.81%) presented a tumor with progressive growth in the anterior cervical region, usually painless and accompanied by local compressive signs. Histologically, we identified six cases (55%) of diffuse large B-cell lymphoma, three cases (27%) of extranodal marginal zone lymphoma, one case (9%) of follicular lymphoma, and one case (9%) of mixed follicular-diffuse lymphoma. PTL was associated with microscopic Hashimoto autoimmune thyroiditis in ten cases (90.9%). Ten patients (90.9%) presented with localized disease (stage I-IIE). A percentage of 60% of patients survived over 5 years. We observed an overall longer survival in patients under 70 years of age. Conclusions: PTL represents a diagnosis that needs to be taken into account, especially in women with a history of Hashimoto autoimmune thyroiditis, presenting a cervical tumor with progressive growth. PTL is a lymphoid neoplasia with favorable outcome, with relatively long survival if it is diagnosed at younger ages.

Collision Tumors of the Colon and Peritoneum: Signet-Ring Cell Carcinoma and Granular Cell Tumor.

Collision tumors, although rare, characterized by two distinctive (morphological, as well immunohistochemical) and spatially independent tumor components at the same location, are always puzzling for clinicians, pathologists, and patients because they do not fit into the usual approaches, being neither diagnostic nor therapeutic. Reviewing the specialized literature, to date, collision tumors have been reported in multiple locations such as the skin, esophagus, stomach, intestine, liver, kidney, bladder, adrenal gland, or thyroid. We report a case of coexistence at the same site of a malignant tumor of the ascending colon and a benign tumor emerging from the peritoneal lining, initially thought by the surgeon to be right-sided serosal carcinomatosis. But histopathological examination reveals that those multiple serosal nodules were benign granular cell tumors that have collided with highly aggressive transparietal signet-ring colon carcinoma. These results put the patient's prognosis and therapeutic strategy in a different light than the clinical and intraoperative evaluation.