Thymic carcinoid with multiple bone metastases: A case report

Thymic carcinoid (TC) is a rare entity among anterior mediastinal malignancies. TCs are neuroendocrine carcinomas that constitute approximately 2%-5% of all thymic epithelial tumors.

The study reported a rare TC with multiple bone metastases. A 77-year-old man presented with a 2-month history of lower back pain and weight loss of 5 kg. Magnetic resonance imaging scans revealed damage to the lumbar spine, sacrocaudal vertebrae and iliac crest, suggesting bone metastasis; computed tomography (CT) scan of the thorax showed a calcified anterior mediastinal mass; positron emission tomography-CT demonstrated multiple abnormal bone signals; and laboratory work-up showed no endocrine abnormalities. Fine-needle aspiration biopsy revealed predominantly single small, round to oval cells with scant cytoplasm and some loose clusters, suggesting endocrine manifestations. The pathological diagnosis was atypical carcinoid, which tend to originate from the thymus and was classified as intermediate-highly invasive. The patient underwent anlotinib-targeted therapy. Anlotinib (12 mg) was administered daily for 2 wk, after which the patient was allowed to rest for 21 d. Follow-up CT after one year demonstrated that the tumor had shrunk by approximately 29% after therapy. Treatment has a long stable disease benefit of more than 2.5 years.

These findings demonstrated that anlotinib is a promising treatment regimen for patients with TC and multiple bone metastases.