Prostatic Adenocarcinoma Metastasis in the Thyroid Gland

Abstract

Abstract. Metastasis from prostate to thyroid gland is very uncommon. Here we report a 77-year-old man who was admitted to the hospital because of a nodular goiter. A fine-needle aspiration biopsy of the nodule showed metastatic prostatic adenocarcinoma. This is the second case of a metastatic prostate carcinoma to the thyroid gland.Key words: Thyroid metastasis, Prostatic adenocarcinoma, Fine needle aspiration cytology (Endocrine Journal 51: 445-448, 2004) OWING to its rich vascular supply, the thyroid gland is a common site of metastasis from malignant tumors elsewhere. The most common sites of origin are breast, kidney, lung, gastrointestinal tract as well as lymphoma and squamous carcinoma of the head and neck region, and melanoma [1][2][3]. Prostate cancer is the second leading cause of cancer death, after lung cancer, among males [4]. The most frequent sites of metastatic prostate carcinoma are regional lymph nodes, followed by bone, lung, bladder, liver, and adrenal gland [5]. Here, we report an unusual metastasis of prostatic carcinoma presented as a thyroid nodule. Case ReportA 77-year-old man with prostatic carcinoma was referred to our department for a nodular goiter. According to the patient's history, the nodule was present for one year and was slowly growing. Medical history revealed that prostatic adenocarcinoma (Gleason grade 4 + 5) was diagnosed after transurethral prostatectomy two years ago. Prostatic cancer located in the right lobe of the prostatic gland. Preoperative PSA level was 84.08 ng/ml (normal: 0-4 ng/ml). Combined androgen blockade (CAB) therapy consisted of gonadotrophine-releasing hormone analogue (leuprolide acetate) and bikalutamide was started. After 20 months of stable disease, PSA level rose to 127 ng/ml and lumbar vertebrae and bilateral shoulder metastases were detected. Thereafter, owing to the persistence of the patient's complaints and high PSA levels bilateral orchiectomy was performed.Clinical examination revealed a hard, palpable, painless, 2 × 1 cm nodule in the right lobe of the thyroid gland. The nodule was slightly movable on swallowing. Chest X-ray, complete blood count and serum biochemistry were normal. Thyroid-stimulating hormone (TSH), free triiodothyronine (fT 3 ), and free thyroxine (fT 4 ) were 0.42 mU/ml (normal: 0.1-4 mU/ml), 2.01 pg/ml (normal: 1.62-3.76 pg/ml), and 1.2 ng/dl (normal: 0.89-1.78 ng/dl), respectively. Thyroid autoantibodies including anti-thyroglobulin and antithyroid peroxidase were negative. Thyroid scan revealed a large "cold" nodule (Fig. 1); ultrasonographic examination showed a solid 2 × 2 cm in size nodule with a nonhomogeneous structure in the right lobe of the thyroid gland (Fig. 2).

Metastases to the thyroid gland: seventeen cases operated on in a single clinical center

“…Similarly, as in the case reported in the literature, the present authors also noted in one woman a simultaneous metastasis to the submandibular gland, and the lesion was excised during the thyroidectomy [2].…”

“…In such cases, the role of FNAB is very important in view of the fact that as a rule, only a single cold nodule is present in the thyroid gland. The value of FNAB in the diagnostic management of thyroid lesions is also emphasized by other authors [2,8,12,26]. In the present material, only in four cases was the FNAB result negative and the diagnosis was established by postoperative histology only.…”

“…Based on the analysis of the literature and their materials, the authors postulate that one of the most common cancers that metastasizes to the thyroid [2,8,9,23] is clear cell cancer of the kidney, which was observed in as many as 13 (78%) of 17 patients in the present series. The literature reports synchronic metastases of clear cell cancer of the kidney as occurring in as many as 25% of cases (3).…”

“…The incidence of such metastases differs depending on the type of the analyzed material. In clinical papers, the incidence is low and, according to various sources, amounts to 2-3% of all malignant tumors of the thyroid [1,2]. In postmortem examinations, the value ranges from 1.25 to 24.2% and is usually associated with cancer dissemination through blood from a distant focus or with a direct involvement of the thyroid gland by a neoplastic process situated in the adjacent organs [3][4][5][6].…”

“…The reason for such a phenomenon is primarily the rapid progress of the primary neoplastic disease (e.g., breast or bronchial cancer) [11,12]. In the vast majority of cases, metachronic hematogenic metastases of renal carcinoma to the thyroid develop a long time after the surgical excision of the primary lesion, e.g., after a nephrectomy performed in a clear cell carcinoma of the kidney [2,13], especially in cases of primary foci of a low clinical grade (15). The literature also provides clinical descriptions of metastases to the thyroid gland occurring in patients with other cancers such as cancer of the prostate, pancreas, uterus, ovaries, and melanoma [5, 8, 14-19, 24, 25].…”