Approach to a Mass of Unknown Significance Location Kinetics Systemic Manifestations

Differential Diagnosis of an Anterior Mediastinal Mass Thymoma Germ Cell Tumor/Teratoma Lymphoma

Shipp M et al. N Engl J Med 2005;352: Differential Diagnosis of an Anterior Mediastinal Mass

Malignancy Infection Granulomatous Disease Benign Tumors Others

Our Patient

Familial Adenomatous Polyposis (FAP) Autosomal Dominant Disease High penetrance (almost ~100) Mean age of onset ,000s of colonic polyps Average age of colon cancer is 39 Accounts for ~1% of all colorectal cancers

Genetics of FAP Classic FAP caused by mutation in APC gene Accounts for 90% of cases Discovered at Johns Hopkins by Kenneth Kinzler and Bert Vogelstein Genetic Test commercially available

FAP Unaffected

Management of FAP Surveillance with annual colonoscopies Colectomy is recommended when polyps are large, dysplastic or with villous histology Patients with small and/or sparse polyps can be followed and schedule colectomy after graduation from High School Total proctocolectomy with ileoanal pouch Subtotal colectomy with ileorectoal anastomsosis

Classic Metastatic Colon Cancer to Lung

MalignancyAbsolute Lifetime Risk (%) Colon100 Duodenum3.0–5.0 Thyroid2.0 Brain (Meduloblastoma)2.0 Ampullary1.7 Pancreas1.7 Hepatoblastoma1.6 Gastric0.6* Extracolonic Malignancies in FAP patients

DESMOID TUMORS Benign Slow Growing Tumors Develop in 10-15% of patients with FAP Typically intra-abdominal and arise at sites of trauma (ie Surgery) Composed of spindle cells and abundant fibrous stroma

Final Differential Diagnosis Atrial Myxoma Indolent Lymphoma Proliferative Fibrosing Mediastinitis

DIAGNOSIS Desmoid Tumor arising in site of Surgical trauma (CABG in 2002) in a patient with FAP