Non-metastatic squamous cell carcinoma within a Rathke's cleft cyst.

INTRODUCTION: Primary intracranial and sellar squamous cell carcinoma is an extremely rare entity, usually caused by malignant transformation of epidermoid cysts, or very rarely other non-malignant epithelial cysts. Malignant transformation of a Rathke's cleft cyst has never been described. CASE DESCRIPTION: We present a 49-year-old male patient who presented with a 3-month history of progressive frontotemporal headaches. Imaging revealed a 1.2 cm cystic pituitary mass consistent with a hemorrhagic Rathke's cleft cyst. The patient underwent trans-sphenoidal resection of the pituitary cyst, and pathologic analysis revealed a squamous cell carcinoma lining a Rathke's cleft cyst. Extensive imaging and otorhinolaryngologic evaluation revealed no primary source for metastasis. CONCLUSIONS: We feel this represents the first case of a patient with a pituitary lesion in which presentation and MRI imaging were consistent with Rathke's cleft cyst, yet histology revealed squamous cell carcinoma in situ.

Concurrent Intrathyroidal Thyroid Cancer and Thyroid Cancer in Struma Ovarii: A Case Report and Literature Review.

CONTEXT: The presence of differentiated thyroid cancer in mature cystic teratomas in the ovaries is rare, and usually incidentally found on surgical pathology specimens. We present a case of simultaneous intrathyroidal thyroid cancer and thyroid cancer within a struma ovarii, presenting specific diagnostic challenges. CASE DESCRIPTION: A 55-year-old woman had an intrathyroidal, encapsulated 1.2-cm papillary thyroid carcinoma, follicular variant, which was resected. Laboratory studies showed an elevated thyroglobulin level of 35 ng/mL while on suppressive levothyroxine therapy. During preparation for radioactive iodine ablation, thyroglobulin increased dramatically to 3490 ng/mL. A pretreatment whole-body scan showed residual tracer uptake in the thyroid bed and increased radiotracer uptake in the pelvis that raised concern for a pelvic metastasis, given the marked thyroglobulin elevation. After ablation, the posttreatment scan showed intense focal uptake in the pelvis. Single-photon emission computed tomography-computed tomography confirmed that the tracer uptake corresponded to a right adnexal mass. The patient underwent a laparoscopic bilateral salpingo-oophorecotomy with pelvic washings. The final pathology of the right ovary showed papillary thyroid carcinoma arising in a mature cystic teratoma. In addition, there was abundant normal thyroid tissue with colloid surrounding the carcinoma, indicating a source for the dramatic rise in thyroglobulin levels and suggesting that the ovarian papillary thyroid cancer arose within the teratoma and was not metastatic disease. Thyroglobulin measurements have been undetectable for 5 years since surgery and radioiodine treatment. CONCLUSIONS: Concurrent intrathyroidal thyroid cancer and differentiated thyroid cancer in struma ovarii are very rare, but can often be distinguished on clinical grounds.

Dichotomous responses to thyroid hormone treatment in a patient with primary hypothyroidism and thyroid hormone resistance.

BACKGROUND: Resistance to thyroid hormone (RTH) is a rare syndrome of reduced TH sensitivity most often due to mutations affecting the ß-isoform of the thyroid hormone receptor (TRß). Patients with RTH may develop hypothyroidism as a result of surgery, mistreatment with radioiodine, or autoimmune thyroid disease. PATIENT FINDINGS: We describe a patient who underwent partial thyroid lobectomy for benign goiter at age 17 and remained healthy through five uncomplicated pregnancies before abnormal laboratory results were noted. She was followed by multiple consecutive specialists after age 40, intermittently treated with levothyroxine, and referred to our clinic at age 66 because of severe progressive fatigue and abnormal thyroid function tests. Initial workup revealed elevated TH levels and inappropriately elevated thyroid-stimulating hormone. TH levels progressively declined into the normal range, accompanied by marked thyroid-stimulating hormone elevation. Antibody testing and thyroid biopsy confirmed Hashimoto's thyroiditis, and genetic testing revealed a TRß mutation. Patient response to TH therapy has been good although limited by palpitations. CONCLUSIONS: Patients with RTH may develop significant hypothyroidism with normal TH levels in the setting of Hashimoto's thyroiditis. RTH presents a unique challenge in both the diagnosis and management of autoimmune hypothyroidism.