title: [Increased glucose uptake by seborrheic keratosis on PET scan].
abstract: BACKGROUND
  Positron emission tomography (PET) is an examination based upon the uptake of a radioactive tracer by hypermetabolic cells. It is primarily used in tandem with tomodensitometry (PET-TDM) for cancer staging because of its high sensitivity and specificity for the detection of metastases. However, unusually high uptake may occur with benign tumours, including skin tumours. Herein, we report an extremely rare case of pathological uptake levels resulting from seborrhoeic keratosis.
  
  
  METHODS
  A 55-year-old male patient with oesophageal squamous-cell carcinoma was referred to us following the discovery of an area of high marker uptake following PET-TDM and corresponding to a pigmented skin lesion. No other areas of suspect high uptake were seen. The lesion was surgically excised and histological examination indicated seborrhoeic keratosis. The histological appearance was that of standard seborrhoeic keratosis without any notable mitotic activity.
  
  
  CONCLUSIONS
  PET-TDM is an examination that enables diagnosis of malignancy. However, rare cases have been described of increased marker uptake by benign cutaneous tumours such as histiocytofibroma, pilomatricoma and condyloma. To date, there have only been only very few cases of increased uptake due to seborrhoeic keratosis.
  
  
  CONCLUSIONS
  This extremely unusual case of increased glucose uptake in PET-TDM due to seborrhoeic keratosis confirms that the hypermetabolic activity detected by this examination is not necessarily synonymous with malignancy and that confirmation by clinical and histological findings is essential. The reasons for increased metabolic activity within such benign tumours are not known.
authors.affiliation: Clinique dermatologique, hôpitaux universitaires de Strasbourg, 1, place de l'Hôpital, 67000 Strasbourg, France. Electronic address: merklencarine@yahoo.fr.
authors.forename: C
authors.initials: C
authors.lastname: Merklen-Djafri
authors.affiliation: Département de radiothérapie, centre Paul-Strauss, 3, rue de la Porte-de-l'Hôpital, 67000 Strasbourg, France.
authors.forename: P
authors.initials: P
authors.lastname: Truntzer
authors.affiliation: Département de médecine nucléaire, centre Paul-Strauss, 3, rue de la Porte-de-l'Hôpital, 67000 Strasbourg, France.
authors.forename: S
authors.initials: S
authors.lastname: Hassler
authors.affiliation: Clinique dermatologique, hôpitaux universitaires de Strasbourg, 1, place de l'Hôpital, 67000 Strasbourg, France.
authors.forename: B
authors.initials: B
authors.lastname: Cribier
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000150:complications; D003937:Diagnosis, Differential; D004938:Esophageal Neoplasms / Q000150:complications; D000077277:Esophageal Squamous Cell Carcinoma; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D017492:Keratosis, Seborrheic / Q000150:complications / Q000000981:diagnostic imaging* / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods; D011230:Precancerous Conditions / Q000150:complications / Q000000981:diagnostic imaging* / Q000378:metabolism*; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity
chemical_list: D005947:Glucose
keywords: 18 FDG; Bilan d’extension; Kératose séborrhéique; Positron emission tomography; Seborrheic keratosis; Staging; TEP-TDM