Rare Metastasis of Gastric Cancer to the Thyroid Gland: A Case Report and Review of Literature

Background: It is common for patients with gastric cancer to develop distant metastases in the liver, lung, bone, and brain. Although the thyroid also has an abundant blood supply, gastric cancer metastasis to the thyroid is uncommon. Due to the rarity of such metastasis, its clinical features are not well understood. Here, we present the case of a patient with gastric cancer metastasis to the thyroid treated at our hospital.Case Summary: We report the case of a 63-year-old female with a mass in the anterior neck and mild hoarseness for 6 months. The patient underwent proximal subtotal gastrectomy for Siewert III oesophagogastric junction cancer 6 years ago. Subsequently, she received 8 cycles of adjuvant chemotherapy. Her condition was stable until mild hoarseness developed for no apparent reason 6 months prior to presenting at our clinic. Both ultrasonography and computed tomography confirmed a heterogeneous mass in the right lobe of the thyroid gland. Blood thyroid function tests and tumor marker expression levels were normal. Thyroid malignancy was suspected, and the patient underwent a right thyroidectomy. During the surgery, a tumor was found that had invaded the right recurrent laryngeal nerve and trachea. H&E staining and immunohistochemistry results suggested that the cancer cells originated from gastric cancer. The patient was diagnosed with thyroid metastasis of gastric cancer. She refused further treatment and died within 6 months.Conclusion: Metastasis of gastric cancer to the thyroid is rare and is associated with a poor prognosis. Immunohistochemical diagnosis is essential for a conclusive diagnosis. For patients with a history of malignant tumors, the possibility of metastatic thyroid nodules should be ruled out when diagnosing thyroid nodules.

DISTANT METASTASIS TO THE THYROID GLAND: CLINICAL REVIEW

Background. Metastasis to the thyroid from non-thyroid sites is an uncommon clinical presentation in oncology practice. Renal cell carcinoma is most common primary cancer, followed by breast cancer metastases, small cell lung carcinoma, colorectal cancer, malignant melanoma, malignancies of the gastrointestinal cancer. However, given that thyroid nodules are most common in women, and women with a history of urogenital malignancy are at higher risk of developing thyroid cancer, the possibility of metastatic thyroid cancer must be considered while evaluating a thyroid lump. Aim: to investigate patient management while finding distant metastases to the thyroid and identification of the most common complications. Material and methods. Identified reports of patients with thyroid metastasis were analyzed in the current literature review. Both clinical and autopsy series were included. Results. Metastases to the thyroid gland may be discovered at the time of diagnosis of the primary cancer, after preoperative investigation or due to histological examination of an operative specimen. In autopsy series, the most common primary site of metastatic thyroid tumors is lung cancer. In a clinical setting, renal cell carcinoma is the most common. Otherwise, when patients present with isolated metastases during follow-up of indolent disease, surgery might provide central neck control and even long-term cure. Prognosis may also vary according to the morphological features of primary cancer, time interval between initial diagnosis and metastasis and presence of extrathyroid invasion. Conclusions. Although the thyroid gland is highly vascularized, metastasis of malignant tumors to the thyroid is relatively rare and detection of metastasis shows a low frequency. A past history of malignant neoplasm should raise the index of suspicious of metastatic disease in patients with thyroid nodules with or without cervical lymphadenopathy. In such patients communication among clinicians treating the thyroid and the primary tumor is essential, as there are differences in treatment protocols and prognosis when compared to primary thyroid cancers. The setting is complex, and decisions must be made considering the localization of primary site, features of the primary tumor and comorbidities. Careful balancing of these factors influences effective patient management and long-term survival.

A Rare Case of Uterine Leiomyosarcoma with Metastasis to the Thyroid Gland

Uterine leiomyosarcomas are aggressive tumors associated with a poor prognosis. These neoplasms have high metastatic potential, more frequently affecting the lungs, liver, and peritoneum. There are very few cases of metastasis to the thyroid described in the literature. We present the case of a 47-year-old female diagnosed with uterine leiomyosarcoma metastatic to the thyroid gland. In this case report, we want to emphasize the utility of ancillary studies to help differentiate a leiomyosarcoma from anaplastic thyroid carcinoma since cytologic evaluation alone can be challenging.

SAT-128 An Uncommon Case of Squamous Cell Carcinoma of the Vulva with Metastasis to the Thyroid Gland

Background: Distant metastasis from Squamous Cell Carcinoma (SCC) of the Vulva is very rare and typically associated with poor outcomes. In the literature, there have been no reported cases of vulvar SCC with metastasis to the thyroid, which augments the uniqueness of the case we are presenting. Clinical Case: A 29-year-old female was hospitalized for abdominal pain & altered mental status. Labs showed calcium 21 (RR 8.5-10.5 mg/dL) with iPTH 4.3 (RR 12-88 pg/mL). Imaging revealed an 8.6 x 7.2 cm right thyroid mass (solid with cystic internal components, hyperechoic to isoechoic, wider than tall, lobulated margins, punctate echogenic foci occupying nearly the entire right lobe, minimal vascularity), mildly effacing the trachea. There were also extensive lesions consistent with systemic metastasis involving the left hilar lymph nodes, pre-tracheal lymph nodes, right hepatic lobe, head of pancreas, retroperitoneal lymph nodes, right inferior pubic ramus, proximal right humerus, left humerus, proximal femur & frontal lobe of the brain. Hypercalcemia of malignancy from an unknown cancer was diagnosed. FNA biopsy of the thyroid mass was consistent with atypia of undetermined significance. Liver biopsy showed evidence of high grade carcinoma with non-calcitonin producing neuroendocrine differentiation. Labs showed serum serotonin 11 (RR 56-244 ng/mL), CA 19-9 < 0.8 (RR 0-35 U/mL), alpha-fetoprotein 2.12 (RR 0-9 ng/mL), CEA 20.97 (RR 0-2.9 ng/mL), PTHrP 33 (RR 14-27 pg/mL), 1,25OH Vit D 18 (RR 18-72 pg/mL), chromogranin A 189 (RR 25-140 pg/mL), & calcitonin < 2 (RR < 5 pg/mL). A vaginal lesion was discovered on exam & biopsy showed squamous cells with cytopathic effect of Herpes Simplex Virus (confirmed with immunohistochemical stain). Subsequent biopsy of the brain & core needle biopsy of the thyroid showed morphology similar to a concurrent biopsy of a vulvar lesion also found on exam: poorly differentiated SCC. The patient was diagnosed with vulvar SCC with extensive metastasis. Her hospital course was complicated by atrial fibrillation, acute respiratory failure, & sepsis. She, unfortunately, passed away from her severe morbidities. Discussion: Metastasis to the thyroid is an infrequent occurrence. It is commonly encountered in breast, lung & renal cell carcinomas. It can occur due to direct spread from adjacent tissues or by lymphatic or hematogenous spread. Thyroid gland metastasis is more commonly seen in patients with aggressive or widespread carcinomas, especially by hematogenous route, due to the thyroid’s extensive vascularity. Conclusion: Thyroid gland metastasis, particularly due to vulvar SCC, is a rare entity with a poor prognosis. In patients with extensive poorly differentiated carcinoma such as our patient, it is of utmost importance to identify suspicious thyroid nodules and perform comprehensive diagnostic testing to facilitate timely intervention for improved outcomes.