Use of PSMA PET/CT to detect prostate cancer metastatic to a preexisting thyroid nodule

Prostate cancer (PCa) seldom metastasizes to the thyroid gland, and only a limited number of cases are documented in the literature. The application of a relatively recent and highly sensitive imaging technique, prostate-specific membrane antigen (PSMA) positron emission tomography-computed tomography (PET/CT), has enhanced the identification of metastatic disease. Nevertheless, as PSMA is expressed in various tissue types, the clinical importance of a PSMA-avid thyroid lesion remains largely uncertain. A minor, yet noteworthy, percentage of these lesions are ultimately determined to be malignant. Here we describe the case of a 70-year-old man with a past medical history of Lynch syndrome who presented to an outpatient oncologic clinic for management of very high risk localized PCa. He developed metastatic recurrence and his disease progressed through several lines of therapy, including immunotherapy and targeted treatments. He was found to have a new, intense PSMA uptake in an existing, previously benign thyroid nodule. Sonographic evaluation revealed changing morphology despite grossly stable size. Repeat biopsy confirmed the unusual finding of PCa metastasis to a known thyroid nodule. The shift in PSMA avidity played a pivotal role in discerning this metastatic deposit. There is a potential risk that such lesions may be inadequately acknowledged. The impact of the patient's Lynch syndrome on this presentation remains uncertain.

Two-year follow-up of a thyroid cartilage metastasis from prostate cancer: A case report

Few case reports describe metastatic prostate cancer to the thyroid cartilage. While earlier reports identified the metastatic lesions upon developing symptoms, more recent ones have detected them via prostate-specific membrane antigen positron emission tomography (PSMA PET). Herein, we report the case of a patient with metastatic castrate-resistant prostate cancer and a PSMA PET-detected lesion in the thyroid cartilage. Over the course of 2 years, he received multiple lines of chemotherapy and hormonal therapy, and his overall disease status fluctuated - some nodal and bony metastases resolved while others appeared anew. His thyroid cartilage lesion, however, slowly progressed in a consistent fashion with increasing uptake on successive PSMA PET images. Apart from mild dysphonia, the patient remained to be asymptomatic from this lesion, and no local therapies were used. To our knowledge, this is the first close follow-up of prostate cancer metastatic to the thyroid cartilage, shedding light on the course of such lesions and helping answer management-related questions, which are particularly relevant as more occult metastases are discovered in the PSMA PET era.

An update on the current epidemiological status of metastatic neoplasms to the thyroid

Secondary tumours to the thyroid gland are uncommon with an overall prevalence of 5.9% in autopsy studies. In recent clinical series, secondary thyroid cancer is seen in only 1.9% of malignant thyroids. There is no gender predominance both overall (female to male 1.07:1) and when stratified by common histological subtypes (renal cell carcinoma, lung adenocarcinoma and colorectal adenocarcinoma). The median age of patients diagnosed with metastatic thyroid tumours in major studies ranges from 54 to 68 years. Metastases are more frequent in patients with pre-existing or concurrent thyroid pathology. In autopsy studies, the most common primary sites are breast carcinoma and lung carcinoma. Renal cell carcinoma, lung carcinoma and breast carcinoma predominate in clinical series. Upper aerodigestive tract primaries often directly infiltrate the thyroid gland. The underlying frequency of a histological subtype, geographic prevalence and aggressiveness of primary cancer likely contributes to the incidence of metastasis in the thyroid gland. This is seen in case series from Asia where gastric and oesophageal primary cancers predominate. Secondary thyroid cancer can present metachronously (60%), synchronously (34%), or as the first presentation of the underlying cancer (6%). Late metastases and first clinical presentations of disease often originate from renal cell carcinomas while synchronous cases tend to originate from the lungs. Other common primary sites for first presentation of secondary thyroid cancer include the lung and oesophagus. Although rare, secondary thyroid cancer should be considered as a differential particularly in patients with previous malignancy, such as from the kidney, lung, or breast.

PSMA-Positive Follicular Thyroid Carcinoma Incidentally Detected by [68Ga]Ga-PSMA-11 PET/CT: Correlation with Immunohistology Confirms Neovascular PSMA-Expression

We present an interesting image of an intense PSMA-positive follicular thyroid carcinoma incidentally detected by [⁶⁸Ga]Ga-PSMA-11 PET/CT in a 76-year-old man with biochemical recurrence of prostate cancer. Immunohistochemical staining demonstrated PSMA expression in the endothelial cells of tumor tissue. This interesting image should remind colleagues to consider malignant thyroid neoplasia in PSMA-positive thyroid lesions.

Isolated multiple bilateral thyroid metastases from prostatic adenocarcinoma: case report and literature review

Solitary metastasis from prostate adenocarcinoma to thyroid gland is very rare and usually associated with other distal metastasis. This report describes for the first time isolated multiple bilateral thyroid metastasis from prostatic adenocarcinoma. A 67-year-old man who is known as a case of prostatic adenocarcinoma was admitted to a hospital as a case of a multinodular goiter on the basis of clinical and CT scan findings. Total thyroidectomy was performed and histopathology result showed adenomatous goiter containing bilateral metastatic prostatic adenocarcinoma. This is the first report of isolated multiple bilateral thyroid gland metastasis from prostatic adenocarcinoma without other distal metastasis. Such lesions are very rare and can be misdiagnosed, so high index of suspicion for thyroid metastasis should be always maintained in all oncology patients with isolated thyroid mass because early resection and thyroidectomy will change the prognosis for patient.

Metastasis of dermatofibrosarcoma from the abdominal wall to the thyroid gland: case report

Metastases in the thyroid gland are very rare. Even the rarer are sarcoma metastases. A 52-year-old woman was referred to our department for evaluation of a nodule in the right lobe of the thyroid gland. She had a history dermatosarcoma of the abdominal wall with known metastasis in the lung. Clinically she had neck pain and worsened swallowing. Objective assessment (ultrasound, computed tomography, and magnetic resonance) indicated a voluminous right lobe nodule with mechanical syndrome, and a fine-needle aspiration biopsy revealed a very suspicious malignant finding. After surgery, the diagnosis was metastasis of dermatofibrosarcoma protuberans. Subsequent treatment was radio- and chemotherapy.

Metastases to the thyroid: a review of the literature from the last decade

BACKGROUND

Although clinically evident metastases of nonthyroid malignancies (NTMs) to the thyroid gland are uncommon, it is important to suspect them in patients who present with a new thyroid mass and a history, however far back, of prior malignancy. In fact, metastases from NTMs to the thyroid gland have been reported in 1.4%-3% of all patients who have surgery for suspected cancer in the thyroid gland. Here we review the literature over the last decade regarding this topic.

SUMMARY

Based on recent literature, the most common NTMs that metastasize to the thyroid gland are renal cell (48.1%), colorectal (10.4%), lung (8.3%), and breast carcinoma (7.8%), and sarcoma (4.0%). Metastases of NTMs to the thyroid are more common in women than men (female to male ratio=1.4 to 1) and in nodular thyroid glands (44.2%). The mean and median intervals between diagnosing NTMs and their metastases to thyroid gland are 69.9 and 53 months, respectively. In 20% of cases the diagnosis of the NTM and its metastases to the thyroid was synchronous. Recent reports indicate that there is a higher frequency of sarcoma metastasizing to the thyroid gland than reported in prior years. Fine-needle aspiration biopsy (FNAB) of thyroid masses is useful in diagnosis of thyroid metastases. However, this requires information about the NTM so that the proper antibodies can be used for immunohistochemical analysis; therefore it is of lesser utility if the NTM is occult. In patients with preexisting thyroid pathology the FNAB diagnosis can be more difficult due to more than one lesion being present.

CONCLUSIONS

It is important to keep in mind that the thyroid gland can be a site of metastases for a variety of tumors when evaluating a thyroid nodule, especially in a patient with a prior history of malignancy. In patients with thyroid lesions and a history of malignant disease, regardless of time elapsed since the initial diagnosis of the primary neoplasm, disease recurrence or progression of malignancy must be considered until proven otherwise.

[Rare locations of metastases from prostate cancer]

The bone tissue is the most frequent site for prostate carcinoma metastasis. Nevertheless many other areas have also been described. Using Pubmed and Cochrane the most exhaustive research possible has been carried out to list these secondary prostate carcinoma lesions.