Clara S. Heffess

BACKGROUND: Clear cell tumors of the thyroid gland in general are uncommon. Metastatic renal cell carcinoma (RCC) to the thyroid gland is a rare occurrence but must be considered in the differential diagnosis of a thyroid gland clear cell neoplasm to prevent misclassification, potentially resulting in inappropriate clinical management.METHODS: Thirty‐six cases of metastatic RCC to the thyroid were retrospectively retrieved from the files of the Endocrine Registry of the Armed Forces Institute of Pathology.RESULTS: The tumors occurred in 22 women and 14 men, ages 53–80 years (mean, 64.9 years). Symptoms were present for a mean of 13.0 months. The tumors generally affected a single lobe of the thyroid gland as a solitary mass (n = 30; 83%), measuring 1.0–15.0 cm in diameter (mean, 3.8 cm). Histologically, the tumors were composed of polygonal cells with clear cytoplasm, distinct cell membranes, and small compact eccentric nuclei within a rich vascular network. Diastase‐sensitive, periodic acid–Schiff‐positive material (n = 22; 61%) and/or Oil Red O‐positive material (n = 5; 14%) were noted. Thyroglobulin immunohistochemistry was negative in the foci of metastatic RCC. Although the majority of the patients had documented previous evidence of an RCC (n = 23; 64%) as remotely as 21.8 years before the thyroid metastases (mean, 9.4 years), the metastatic tumor to the thyroid gland was the initial manifestation of RCC in 13 patients. The majority of patients (n = 23; 64%) died with disseminated disease (mean, 4.9 years), but 13 patients (36%) were alive or had died without evidence of disease (mean, 9.1 years).CONCLUSIONS: In the presence of a clear cell tumor of the thyroid gland, the diagnostic considerations must include metastatic RCC. The light microscopic features may suggest this possibility and the diagnosis can be established by supplemental histochemical and immunohistochemical studies. Surgical treatment of the metastatic disease is suggested, as this may result in prolonged patient survival. Cancer 2002;95:1869–78. Published 2002 by the American Cancer Society.DOI 10.1002/cncr.10901

Infiltration of the capsule, vascular invasion, and/or neoplastic extension into the adjacent parenchyma are regarded as prerequisites for the diagnosis of follicular carcinoma. In modern practice,...

Solid-pseudopapillary tumors are uncommon neoplasms of low malignant potential generally occurring in young women. They often cause few symptoms and may reach a large size by the time they are detected. Degenerative cystic changes are common, and the clinical presentation is often that of a cystic pancreatic tumor. Pathological features include solid, cellular, hypervascular regions without gland formation, and degenerative pseudopapillae. The cells contain eosinophilic granules rich in alpha-1-antitrypsin and the nuclei are typically grooved. Despite its characteristic microscopic appearance, the immunophenotype (positive for vimentin, alpha-1-antitrypsin, and neuron specific enolase) is not specific and does not define a line of differentiation corresponding to any normal pancreatic cell type. Ultrastructural studies have also failed to identify specific differentiated features. Nonetheless, the biological behavior of solid-pseudopapillary tumor is well established. The tumor is indolent, with infrequent metastases to liver or peritoneum and usually long survival, even in the presence of disseminated disease.

Thyroid papillary carcinoma of columnar cell type is considered an uncommon histologic subtype of papillary carcinoma characterized by its morphologic features and purportedly aggressive biologic course. Sixteen cases of thyroid papillary carcinoma of columnar cell type were identified from the Endocrine Tumor Registry at the Armed Forces Institute of Pathology and the Washington Hospital Center. Clinical records and follow-up were available in all cases. Paraffin blocks were available for histochemical and immunohistochemical studies in 15 of the 16 cases. Of the 16 cases reported, 13 patients were female and 3 were male. The ages ranged from 16-76 years (average, 47 years; median, 40 years). An asymptomatic neck mass was the most common clinical presenting symptom. Macroscopically, the tumors varied from circumscribed or encapsulated to infiltrative, ranging in size from 1.5-6.5 cm. Histologically, the tumors had diverse growth patterns, including papillary, solid, microfollicular, and cribriform. A common pattern was the presence of markedly elongated follicles arranged in parallel cords. Colloid-filled follicles could be found, at least focally, in all cases. The characteristic histologic appearance included the presence of elongated cells showing nuclear stratification. Other features included the presence of vacuolated-appearing cells, spindle-shaped cells, and squamoid nests. Limited areas in the tumors showed morphologic features typical of thyroid papillary carcinoma. In 14 of the cases, the tumor was encapsulated, showed limited invasive growth, or was a microscopic tumor. In two of the cases, there was extrathyroidal invasion. Immunohistochemical studies showed consistent reactivity with cytokeratin and vimentin; varied reactivity with thyroglobulin, epithelial membrane antigen, carcinoembryonic antigen, and LeuM1; and no reactivity with calcitonin or chromogranin. Treatment was by surgical resection; supplemental radioactive iodine therapy was administered in eight patients. Follow-up was available for all patients, 13 of whom (81%) were alive and free of disease or had died of unrelated causes over periods ranging from 2-11 years (average, 5.8 years). All 13 of these patients had tumor confined completely to the thyroid gland. One patient died 4 months after diagnosis secondary to sepsis. Two patients (17%) had aggressive biologic courses. In both patients there was extrathyroidal invasion. One of these patients died of metastatic disease to the lungs 3 years after diagnosis; the other was alive with bilateral pulmonary metastases 9 years after the diagnosis. The findings of the current study indicate that thyroid papillary carcinoma of columnar cell type is a distinct morphologic type but not a distinct clinical type of thyroid papillary carcinoma. The biologic behavior of this tumor is predicated on clinical stage, with the presence or absence of extrathyroidal invasion being the single most important parameter. Treatment of patients with these tumors should be based on the clinical stage and not on the morphologic appearance.

Adrenal epithelioid angiosarcomas (AEA) are rare neoplasms. We report the clinicopathologic features of nine cases of AEA. AEA occurred most frequently in the sixth and seventh decades of life (age range, 45-85 years; median, 60); five cases occurred in men and four in women. Presenting symptoms included abdominal mass with or without pain, weight loss, fever, and weakness. Two cases were asymptomatic; one was discovered during evaluation for other disease(s) and the other at autopsy. All neoplasms were nonfunctioning. Radiographic evaluation demonstrated suprarenal or retroperitoneal neoplasms ranging in size from 6 to 10 cm in greatest dimension. Histologically, the neoplasms were invasive, predominantly arranged in solid sheets or nests, and composed of epithelioid cells. Endothelial cell differentiation was suggested by the transition areas between dilated anastomotic vascular spaces and the sheet-like growth, the cytomorphologic similarity between the endothelial cells lining the discernible vascular spaces and those seen in the solid foci, and the presence of intracytoplasmic vacuolization occasionally containing red blood cells. Endothelial derivation was confirmed by immunohistochemistry including Factor VIII-related antigen (FVIII), CD-34 (hematopoetic progenitor cell antigen), and/or Ulex europaeus agglutinin-1 lectin immunoreactivity (UEA-1) and by ultrastructural findings, including rod-shaped microtubulated bodies and intracytoplasmic lumen formation. In addition, cytokeratin reactivity was seen in seven cases, and B72.3 (tumor-associated glycoprotein-72) reactivity was seen in six. Surgical resection was the treatment of choice, occasionally supplemented by chemotherapy. Three patients are presently alive, free of disease, at 13, 11, and 6 years following diagnosis. Three died with metastatic AEA of the lung, and three died of unrelated causes.