7925 Cowden Disease Occurring in Association with Common Variable Hypogammaglobulinemia: A Case Report

Abstract Disclosure: M.K. Shakir: None. I.C. Ebrahim: None. D.B. Maxwell: None. N.O. Vietor: None. T.D. Hoang: None. Carriers of a pathogenic germline mutations in the PTEN gene, a tumor suppressor gene, are at increased risk of multiple benign and malignant tumors, including thyroid, breast, endometrial and colon cancer, termed as PTEN Hamartoma Tumor Syndrome (PHTS). Recent studies have shown that PHTS patients may also have an increased risk of immunological dysregulation, such as autoimmunity and immune deficiencies. We are reporting a 47-year-old female with Cowden disease (CD) and common variable hypogammaglobulinemia (CVH). Our patient was diagnosed with CVH at the age of 25 after several episodes of pneumonia as well as poor wound healing. Since then, she is being treated with monthly intravenous immunoglobulin therapy. At the age of 24 years, she had a fainting episode and a diagnosis of gangliocytoma of cerebellum was made and she underwent resection of the tumor. At this time, she was also diagnosed with CD. She has a personal history of multiple other tumors including phyllodes tumor of breast, s/p bilateral mastectomy at the age of 32, status post hysterectomy for endometrial hyperplasia at the age 35. Hurthle cell adenomas of thyroid s/p total thyroidectomy at the age of 38. Her family history was significant for sister and father with CD. Physical examination was remarkable for only acral keratosis without mucocutaneous neuromas, oral papillomas and trichilemmomas. Cowden syndrome is the best-described phenotype of PHTS; it is characterized by mucocutaneous lesions and an elevated risk of breast, thyroid, endometrial, colorectal, and renal cancers as well as various benign manifestations such as macrocephaly and dysplastic gangliocytoma of the cerebellum. Our patient was diagnosed with CD when she presented with gangliocytoma of the cerebellum. Immunodeficiency has been reported previously in patients with CD, and these patients often present with recurrent cellulitis and abscesses, and reduced T cell numbers and in vitro T cell proliferative function. Thus, PHTS patients may also have an increased risk of immunological dysregulation, such as autoimmunity and immune deficiencies. Additionally, a decreased ability of dendritic cells to prime CD8+ T cells may occur, leading to impaired tumor eradication. Immune dysfunction in PHTS patients might be a potentially manageable contributing factor to the increased cancer risk in PHTS. In conclusion, patients presenting with CD should also be screened for disorders of immunological dysregulation. Presentation: 6/2/2024