University Hospital of Freiburg Freiburg, Germany
Bruno Allolio, Wiebke Arlt and Carsten Körber
University Hospital of Würzburg, Würzburg, D-98080 Germany
Torpy et al. (1) and Tabarin et al. (2) reported recently a low diagnostic sensitivity of Indium111 pentetreotide scintigraphy as a tool for the localization of ectopic ACTH-producing tumors. de Herder and Lamberts in their editorial comment (3) suggested that, despite these negative results, Indium111 pentetreotide scintigraphy could be helpful in a minority of patients with Cushings disease and should be used in the localization procedure of ectopic ACTH sources. We would like to emphasize this view with a short case report of a recent patient in whom Indium111 pentetreotide scintigraphy remained the only procedure to localize an extremely small ACTH-producing bronchial carcinoid.
A 37-yr-old male patient was admitted with hypokalemic
hypertension, muscle weakness, hyperglycemia, weight gain, facial
swelling, and psychosis. The diagnosis of ACTH-dependent Cushings
syndrome was established. Plasma ACTH and cortisol concentrations were
unresponsive to corticotropin releasing CRH hormone and high dose
dexamethasone, suggesting ectopic Cushings syndrome. The diagnosis
was confirmed by inferior sinus petrosal catherterization, which
demonstrated no gradient between the pituitary and the peripheral ACTH
levels. Computed tomography (CT) and magnetic resonance imaging (MRI)
of chest and abdomen did not visualize the ectopic ACTH source.
Adrenostatic treatment was introduced but failed to control
hypercortisolism. The patient underwent bilateral adrenalectomy. The
postoperative period was uneventful, and the patient recovered from
Cushings syndrome. At follow-up, plasma ACTH concentrations were
steadily increasing, suggesting tumor progression, but CT and MRI scans
of the chest and the abdomen after 3, 6, and 9 months did not identify
the ectopic ACTH source. Indium111 pentetreotide
scintigraphy scanning with 214 Mbq Indium111 octreotide was
performed, revealing a spot in the left lung 24-h post-injection (Figs. 1 and 2
).
In spite of this finding, CT (2 mm slices) and MRI were still unable to
localize the tumor. Exploratory thoracotomy was performed, and an
atypical bronchial carcinoid tumor measuring 0.6 mm in segment 6 of the
lower lobe was resected. This case illustrates that
Indium111 pentetreotide scintigraphy can be of extreme
value in a small minority of patients with the ectopic Cushings
syndrome.
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Footnotes
Address correspondence to: Martin Reineke, M.D., Schwerpunkt Endokrinologie, Abteilung Innere Medizin II, Klinikum der Albert-Ludwigs-Universität Freiburg, Hugstetter Strasse 55, Freiburg, Germany D-79106.
Received May 20, 1999.
References