Dysplastic gangliocytoma (Lhermitte-Duclos disease [LDD]) typically presents as a PTEN (phosphatase and tensin homolog)-positive, insidious unilateral mass of the cerebellar cortex.
The diagnosis of Cowden syndrome with PTEN gene mutation, linked to higher risk of neoplasia and occurrence of hamartomatous lesions characteristic of the Lhermitte-Duclos disease (LDD), was confirmed by genetic investigation.
Lhermitte-Duclos disease is a rare hamartomatous tumor of the cerebellum resulting from a mutation in the phosphatase and tensin homolog (PTEN) gene: it has been reported in fewer than 10 infants.
At 6 months before his death, the patient complained of hoarseness and dysphagia, and clinical whole-body examinations revealed advanced lung adenocarcinoma (T4N2M1b, Stage IV), multiple skin verrucas, gastrointestinal polyposis, goiters, and cerebellar dysplastic gangliocytoma (Lhermitte-Duclos disease), while PTEN gene mutation was detected in his serum.
A PTEN mutation, c.1003C>T p.(Arg335Ter), was subsequently identified as the cause of Cowden syndrome in another family member (a nephew) with dysplastic gangliocytoma of the cerebellum (Lhermitte-Duclos disease), and genetic testing in the proband's daughter indicated that he was an obligate carrier of the mutation.
In addition, the differential PTEN mutation status with corresponding LDD phenotypes suggests a potential correlation between germline or somatic mutation and coexisting LDD/CS or isolated LDD, respectively.
Incidence and clinical characteristics of thyroid cancer in prospective series of individuals with Cowden and Cowden-like syndrome characterized by germline PTEN, SDH, or KLLN alterations.