Solitary cerebellar metastasis from papillary thyroid carcinoma: a case report.

Papillary thyroid carcinoma is a common thyroid malignancy that generally has a good prognosis. However, this type of cancer may give rise to distant metastasis and may behave more aggressively in older patients. Here we report clinical, radiological, and pathological findings of a patient with papillary thyroid carcinoma who had a solitary cerebellar metastasis. The patient was known to have metastatic thyroid cancer to the lungs, but this had been stable and the cerebellar metastasis presented an unanticipated significant problem. The rapid detection of cerebellar metastatic disease is critical because neurosurgical removal of the solitary lesion should be considered as the treatment of choice. This case also serves to remind us of the importance of considering possible metastatic brain lesions and their acute life-threatening complications in contrast to the relatively prolonged course associated with metastases of thyroid carcinoma to other organs.

Microsporidium-associated sinusitis.

Two cases of biopsy-proven Microsporidium-associated chronic sinusitis in HIV-seropositive patients are presented. Spores of Septata intestinalis were identified by light microscopy and confirmed by electron microscopy in each case. Both patients displayed severe deficiencies of nasal mucosa CD4-positive cells, demonstrated by immunohistochemical methods. Only two other cases of Septata intestinalis-associated sinusitis have been reported previously. Our observations agree with the theory that functional defects in local mucosal immunity may partially explain the acquisition of opportunistic mucosal infections in many HIV-seropositive patients.

Oncocytic mucoepidermoid carcinoma of the parotid gland.

Oncocytic mucoepidermoid carcinoma of the salivary gland is rare. We describe a 60-year-old woman who presented with a slowly growing left parotid mass. The patient underwent a total parotidectomy, and her postoperative course was uneventful. The gland was enlarged and showed a partially cystic mass containing clear mucoid material. Microscopically, the entire mass showed variably sized cysts lined predominantly with oncocytes and a few mucous goblet cells. Histochemical stains for mitochondria, such as phosphotungstic acid-hematoxylin, confirmed the presence of oncocytes. The recognition of this variant is important, since most of the other primary oncocytic lesions of the salivary glands are benign. The tumor in this case is considered to be a low-grade carcinoma; therefore, complete surgical excision and long-term clinical follow-up are adequate management.

False-positive lymph nodes by radioimmunoguided surgery: report of a patient and analysis of the problem.

Preoperative administration of radiolabeled monoclonal antibody allows radioimmunoguided surgery with hand-held intraoperative detection devices. From a theoretical perspective, this technology may offer more knowledgable patient management and more complete resection of intra-abdominal cancer. False-positive examinations may seriously jeopardize the widespread application of this apparatus. Our experience with a patient with false-positive lymph nodes following administration of 125I-labeled B72.3 monoclonal antibody is reported. After careful histopathological analysis of five nodes thought to be false-positive for cystadenocarcinoma, one lymph node was found to have a minute nidus of cancer. The cause of false-positive radioimmunoguided tests and their implications for the clinical use of this tool is discussed. We interpreted our data to suggest that tumor antigen-monoclonal antibody complexes processed in reactive lymph nodes, anatomically draining the malignant tissue, may cause false-positive tests.