ESPE Abstracts

Introduction: Phosphatase and tensin homolog (PTEN) is a tumor suppressor gene involved in the PI3K/AKT/mTOR pathway. Mutations in the PTEN gene are known to cause PTEN Hamartoma Tumor Syndrome (PHTS), an autosomal dominant disorder. This syndrome is characterized by proliferative lesions in various tissues, including the thyroid gland, breast, gastrointestinal system, kidneys, and endometrium. We present a patient who initially presented with a breast mass and thyroid nodules due to Hashimoto’s thyroiditis and was subsequently diagnosed with PHTS, highlighting the importance of follow-up.

Case: A 14-year-old female patient presented with a breast mass. Her medical history included follow-up for macrocephaly during infancy. Her weight was 61 kg (+0.91 SD), height 157 cm (-0.65 SD), and head circumference 62.5 cm (+4.15 SD). Physical examination revealed a stage 2 goiter and a 2 cm mass in both breasts. Puberty was at Tanner stage 5 with regular menses. Family history indicated that her father's uncle had thyroid cancer, with no known breast cancer cases in the family. Laboratory tests, including complete blood count, biochemistry, erythrocyte sedimentation rate, beta-HCG, AFP, TSH, and free T4 were normal. Positive anti-TPO and anti-thyroglobulin antibodies were noted. Thyroid ultrasonography identified an isoechoic solid nodule measuring 20 × 11 × 23 mm with central cystic changes and indistinct borders in the left lobe, and a 10 × 5 mm isoechoic solid nodule in the isthmus. Calcitonin and thyroglobulin levels were within normal ranges. Fine-needle aspiration biopsy of the larger nodule was consistent with chronic lymphocytic thyroiditis. Breast ultrasonography revealed two hypoechoic solid nodules measuring 25 × 13 mm and 18 × 8 mm in the periareolar area of the left breast, and a 20 × 8 mm anechoic cyst in the retroareolar area of the right breast. A tru-cut biopsy confirmed fibroadenomas. Genetic testing due to the presence of nodules in both the breast and thyroid revealed a heterozygous c.416T>A (p.Leu139Ter) variant in the PTEN gene, considered pathogenic. Upon the observation of macrocephaly, cranial MRI showed a focal expansion approximately 1x2 cm in size in the extra-axial CSF space at the right cerebellopontine angle, suggestive of an arachnoid cyst. Endocolonoscopy revealed four 5x5 mm hyperplastic polyps, though the patient had no gastrointestinal symptoms.

Conclusion: PHTS should be considered in patients presenting with coexisting breast masses and thyroid nodules, with macrocephaly serving as a guiding finding. Our patient continues to be closely monitored for thyroid nodules, breast fibroadenomas, and gastrointestinal polyps.

Keywords: PTEN, PHTS, thyroid nodule, breast fibroadenoma