The Value of Punching It Out: Patient With Cowden Syndrome and MALT Lymphoma of the Lung.

Introduction: Cowden syndrome (CS) is a phenotypic representation of PTEN hamartoma tumor syndrome. CS is the result of dysregulation of the MTOR pathway contributing to cellular proliferation, which leads to an increased risk for the development of benign and malignant tumors of the breast, thyroid, endometrium, and kidney. There are scarce reports of patients with this condition developing lymphomas. Case Presentation: We present an African American female with a history of MALT lymphoma of the right lung diagnosed at age 41 treated with Rituxan who then presented at age 48 with a triple-negative cancer of the right breast. Physical exam showed macrocephaly, thyromegaly, and palmar pits. Family history was notable for a sister deceased from ovarian cancer at age 21 and a mother deceased from colon cancer at age 61. Genetic testing via peripheral blood identified a heterozygous PTEN pathogenic variant p.R130Q consistent with a molecular diagnosis of CS. Skin biopsy was coordinated given concern the MALT lymphoma could have contributed to spurious results and confirmed the same pathogenic PTEN mutation. Conclusion: Lymphomas have rarely been reported with this condition although activation of the PTEN pathway has been previously reported as a contributing factor in B cell lymphoma. Skin biopsies may offer the best specimen for patients with hematologic malignancy.