Cowden syndrome (CS) is a rare genetic condition due to the various germline mutations
in the phosphatase and tensin homologue on chromosome ten (PTEN) tumour suppressor
gene. As a result, CS is characterised by an increased risk of developing various
benign and malignant tumours, such as thyroid, breast, endometrial and urogenital
neoplasms, as well as gastrointestinal tract tumours. However, the neuroendocrine
tumour association with CS is not elucidated yet. We present a case of a 46-year-old
male patient diagnosed with testicular seminoma and follicular thyroid cancer in his
medical history. Our patient met the clinical diagnostic criteria of Cowden syndrome.
Genetic analysis established the clinical diagnosis; a known heterozygous PTEN mutation
was detected [PTEN (LRG_311t1)c.388 C > T (p.Arg130Ter)]. Incidentally, he was also
seen with multiple pulmonary lesions during his oncological follow-up. A video-assisted
thoracoscopic left lingula wedge resection and later resections from the right lung
were performed. Histological findings revealed typical pulmonary carcinoid tumours
and smaller tumorlets. Somatostatin receptor SPECT-CT, 18F-FDG-PET-CT and 18F-FDOPA-PET-CT
scans and endoscopy procedures could not identify any primary tumours in other locations.
Our patient is the first published case of Cowden syndrome, associated with multifocal
pulmonary carcinoids. Besides multiple endocrine neoplasia type 1, we propose Cowden
syndrome as another hereditary condition predisposing to multiple pulmonary tumorlets
and carcinoid tumours.
