title: Collision/composite tumors of the adrenal gland: a pitfall of scintigraphy imaging and hormone assays in the detection of adrenal metastasis.
abstract: BACKGROUND
  In patients with a history of extraadrenal tumor, incidental discovery of an adrenal mass necessitates excluding the possibility of metastatic malignancy. Detection of the malignant tissue is a difficult challenge when metastasis occurs in an adrenal adenoma, forming a collision/composite tumor.
  
  
  OBJECTIVE
  We report two patients with adrenal collision/composite tumors referred to two French university hospitals.
  
  
  RESULTS
  Two patients with histories of mammary and sigmoid carcinomas, respectively, presented with adrenal mass discovered 8 and 3 yr after surgical removal of the primary tumor. In the two cases, computerized tomographic scan showed that the adrenal tumor contained two components with low and high attenuation values, respectively. Uptake of iodocholesterol by the adrenal tumor in case 1 and elevated plasma ACTH-stimulated 17-hydroxyprogesterone values in case 2 strongly argued for the diagnosis of primary adrenocortical tumors. Enlargement of the adrenal mass during follow-up in case 1 and association of the adrenal lesion with a hepatic mass in case 2 led to adrenalectomy. In both cases, histological examination of the tumor demonstrated the presence of metastatic carcinoma tissue in an adrenocortical adenoma, allowing classification of the neoplasia as a collision/composite tumor.
  
  
  CONCLUSIONS
  These observations show that collision/composite tumors of the adrenal gland formed by carcinoma metastasis in benign adenomas are a pitfall of iodocholesterol scintigraphy and/or plasma steroid assays to exclude the diagnosis of adrenal metastasis. Conversely, computerized tomographic scan is a useful tool for the distinction between the benign and malignant tissues in adrenal collision/composite tumors.
authors.affiliation: Institut National de la Santé et de la Recherche Médicale U413, Department of Endocrinology, Diabetology, and Metabolic Diseases, Hospital of Boisguillaume, Centre Hospitalier Universitaire of Rouen, 76031 Rouen cedex, France.
authors.forename: Adeline
authors.initials: A
authors.lastname: Thorin-Savouré
authors.forename: Frédérique
authors.initials: F
authors.lastname: Tissier-Rible
authors.forename: Laurence
authors.initials: L
authors.lastname: Guignat
authors.forename: Anne
authors.initials: A
authors.lastname: Pellerin
authors.forename: Xavier
authors.initials: X
authors.lastname: Bertagna
authors.forename: Jérome
authors.initials: J
authors.lastname: Bertherat
authors.forename: Hervé
authors.initials: H
authors.lastname: Lefebvre
mesh_terms: D015071:19-Iodocholesterol; D000236:Adenoma / Q000097:blood / Q000000981:diagnostic imaging* / Q000473:pathology*; D000310:Adrenal Gland Neoplasms / Q000097:blood / Q000000981:diagnostic imaging* / Q000556:secondary*; D000324:Adrenocorticotropic Hormone / Q000097:blood; D001943:Breast Neoplasms / Q000473:pathology*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D011877:Radionuclide Imaging; D012811:Sigmoid Neoplasms / Q000473:pathology*; D014057:Tomography, X-Ray Computed
chemical_list: D015071:19-Iodocholesterol; D000324:Adrenocorticotropic Hormone