Subject(s)
Career Choice , General Surgery/education , Internship and Residency , Students, Medical , Adult , Canada , Evaluation Studies as Topic , HumansABSTRACT
Ultrasound biomicroscopy (UBM) remains a potent tool in the diagnosis and characterization of uveal lesions. In the setting of malignancy, it can confirm both placement of and response to brachytherapy. We present a case of iris melanoma with aggressive BAP-1 mutation, treated successfully with I-131 brachytherapy which was both characterized and followed with UBM and thereafter discuss the current state of these modalities.
ABSTRACT
A 40-year-old male presented to the ophthalmology clinic with a darkly pigmented infratemporal lesion in his right eye. The corrected visual acuity in both eyes was 6/6 and both pupils were equal and reactive. Slit lamp biomicroscopy showed a well-demarcated and heavily pigmented lesion in the peripheral iris between 6 and 8 o'clock. Ultrasound biomicroscopy (UBM) revealed a solid mass deriving from the iris stroma without ciliary body involvement, helping to classify the uveal melanoma and establishing the diagnosis of iris melanoma. Fine needle aspiration (FNA) confirmed melanoma with inactivation of the BAP1 gene. The patient was treated with brachytherapy using an I-125 plaque. Follow-up UBM, three years later, demonstrated significantly reduced dimensions of the tumour. UBM has become crucial to the differentiation of uveal melanomas from benign growths, and lesions <3 mm cannot be reliably visualised by other imaging modalities or localised to the correct uveal structure. Brachytherapy represents a safe and effective treatment option even in lesions that are BAP1 positive.
ABSTRACT
BACKGROUND: Thyroid metastases to distant sites are uncommon incidents, most often metastasizing to the lungs and bones. Rates of metastasis to the kidney are particularly low, ranging from 2.8-3.8% for papillary and 6-20% for follicular variants of well-differentiated thyroid cancers (WDTCs). In rare instances, tumor-to-tumor metastasis between two true primary neoplasms can occurs. This medical phenomenon has previously occurred as a clear cell renal cell carcinoma (CCRCC) spreading to a WDTC. To our knowledge, this is the first report of a tumor-to-tumor metastasis of a thyroid cancer metastasizing to a primary renal neoplasm. CASE PRESENTATION: A 72 year old male presented to the urology clinic with complaints of flank pain. Computed tomography (CT) imaging of the abdomen and pelvis revealed a 5.7 cm solid enhancing mass from the lateral aspect of the right kidney, suspicious for renal cell carcinoma (RCC). The patient subsequently underwent a right laparoscopic radical nephrectomy, and immunohistochemical staining of the 5.5 cm lesion revealed a positive RCC marker to establish a diagnosis of a pT1b ISUP Grade 2 CCRCC. The tumor contained a 3 mm focus of a lesion staining positive for TTF1 and Thyroglobulin, and negative for RCC marker. This finding established a diagnosis of a tumor-to-tumor metastasis of PTC to CCRCC. Subsequent ultrasound and CT of the head and neck revealed a heterogeneously hypodense 3.3 cm mass in the right thyroid lobe, prompting a total thyroidectomy and level VI neck dissection. Pathology revealed a classic variant multifocal PTC and two ipsilateral lymph nodes positive for metastatic PTC. Ultimately, the thyroid specimen was positive for lymphatic vascular invasion, extrathyroidal extension with invasion of the tracheal cartilage, staging as T4aN1aM1. On follow up examination the patient was recovering well, without signs of dysphagia or dysphonia, and showed bilateral mobile vocal cords on laryngoscope examination. CONCLUSIONS: Tumor-to-tumor metastasis between the thyroid and kidney is an extremely rare occurrence, reports of RCC metastases from a WDTC has not yet been reported in the literature. Corroboration of diagnostic imaging findings with immunohistochemistry staining can consolidate a diagnosis of thyroid neoplasm tumor-to-tumor metastasis to a RCC, thereby prompting surgical excision.
