Thyroid swelling in a 32-year-old male

Abstract

Patients with intrathyroidal metastasis may present with previous history of malignancy or they may present with a secondary neoplasm prompting us to search for the primary site. A 32-year-old male presented with a 4-month history of thyroid swelling and abdomen pain. Fine-needle aspiration cytology from the thyroid swelling revealed deposits from the mucinous adenocarcinoma. The further diagnostic and metastatic work-up identified a diffuse carcinoma of the stomach as the primary site with liver as secondary and retroperitoneal lymph nodes having mucinous deposits with associated Peutz-Jeghers polyposis. This is the first report in the English literature of intrathyroidal metastasis from carcinoma of the stomach with Peutz-Jeghers polyposis presenting primarily as a thyroid swelling. Preoperative diagnosis, proper evaluation and high degree of suspicion may avoid unnecessary thyroidectomy and effective palliation can be achieved with chemotherapy in view of disseminated disease.

BACKGROUND

Tumours metastasising to the thyroid gland are rare.¹ When it does, it is mostly during the follow-up after treatment of a malignancy; thyroid swelling as a presenting feature is even rarer.^1,2 The commonest primary site is the kidney followed by the breast and lung.^1–3 The metastasis from a stomach primary is very rare and its association has never been reported with Peutz-Jeghers polyposis (PJP). We report a 32-year-old male patient who presented with a triad of thyroid swelling, rectal polyps and anaemia; a clinical diagnosis of primary thyroid neoplasia with possibility of multiple endocrine neoplasia syndrome or Gardner’s syndrome was considered. The differential diagnosis and work-up leading to final diagnosis is discussed.

CASE PRESENTATION

A 32-year-old anaemic male presented with a thyroid swelling and a dull aching abdominal pain of 4 month duration. On examination, there was bilobar multinodular enlargement of the thyroid, hepatomegaly and tenderness in the epigastrium. Rectal examination revealed multiple polyps protruding through the anus.

INVESTIGATIONS

Fine-needle aspiration cytology (FNAC) from the thyroid gland showed mucin secreting adenocarcinoma (fig 1). Upper gastrointestinal endoscopy showed multiple matted small pedunculated polyps of <1 cm in the fundus, body and cardia. The first part of the duodenum was normal, while the second and third part of the duodenum showed pedunculated polyps. A biopsy was taken from the stomach and the duodenal polyps, which revealed diffuse signet ring cell carcinoma (fig 2A) with Peutz-Jeghers polyps (fig 2B). Colonoscopy showed multiple polyps of 2–4 cm size distributed throughout. Biopsy of the colonic polyps also confirmed it to be PJP. Ultrasound of the abdomen revealed multiple peripancreatic, periportal and mesenteric lymph node enlargement and a solitary metastatic deposit in the liver with ascites. Ultrasound guided FNA from retroperitoneal lymph nodes and liver was suggestive of metastatic deposits of mucinous adenocarcinoma. The carcinoembryonic antigen was 29.2ng/ml and chest x ray was normal.

Figure 1.

Aspiration cytology from the thyroid gland (A) showing mucin secreting adenocarcinoma (papanicolaou ×400) and (B) showing signet ring cells and intracellular mucin (Giemsa stain ×400).

Figure 2.

Photomicrograph (A) Duodenal biopsy showing diffuse carcinoma stomach infiltrating duodenum (H&E ×100) and (B) duodenal polyp showing Peutz-Jeghers polyp (H&E ×400).

DIAGNOSIS

A diagnosis of primary signet ring cell carcinoma of the stomach with thyroid and liver metastasis and ascites, T2a N1 M1 stage IV disease and an Eastern Cooperative Oncology Group performance status of 0 was made

TREATMENT

The patient was put on palliative chemotherapy with FOLFOX-4 regimen.

OUTCOME AND FOLLOW-UP

After completion of four cycles, the thyroid swelling has reduced in size and patient has achieved a stable disease.

DISCUSSION

This apparently healthy patient presenting with thyroid swelling posed a question having conjectural answer of diagnosis and management. The presenting triad of anaemia, rectal polyposis with associated thyroid swelling suggested a clinical possibility of Gardner syndrome or familial adenomatous polyposis (FAP).⁴ However, FNAC from the thyroid showing presence of mucinous adenocarcinoma made us think differently. The metastasis to the thyroid gland is of very unusual occurrence and usually has a grim prognosis. In a series of 43 cases, kidney was the most common primary tumour site (33%), followed by lung (16%), breast (16%), oesophagus (9%) and uterus (7%).^5,6 Papi et al⁷ reported the lung as the most common site followed by oesophagus, breast and kidney. Most of these earlier cases had a previous history of cancer contrary to our case where the patient presented with a primary thyroid swelling. Rectal findings of polyps and thyroid FNAC showing a mucinous carcinoma prompted us to investigate the patient further only to find metastatic disease. Although the intestinal lesions are haemartomas, patients with PJP demonstrate a 6 to 16-fold increased risk of developing cancer compared with that of the general population.⁸ There have been many published cases of intrathyroidal metastasis,^5–7 but there is no previous report of the mucin-secreting adenocarcinoma metastasing to the thyroid from the stomach. In patients suspected to have mucin-secreting adenocarcinoma, the diagnostic search for the primary site in male patients should primarily focus on the gastrointestinal tract, prostate, pancreas, lung, breast and kidney.

LEARNING POINTS

• Intrathyroidal metastasis is rare.

• A high degree of suspicion is required when considering the thyroid swelling as metastasis.

• When fine-needle aspiration cytology shows mucin-secreting adenocarcinoma, a search for the primary site in the gastrointestinal tract should be made.

• Disseminated disease is managed with palliative chemotherapy and thyroidectomy is avoided.