Clinical Imaging xxx (2015) xxx–xxx

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Computed tomography and magnetic resonance imaging findings of ureteral myxedema in Graves’ disease☆ Fabio Minutoli a, Caterina Benedetto a,⁎, Carmela Visalli a, Antonio Granata b, Michele Gaeta a a b

Section of Radiological Sciences, Department Biomedical Sciences and of Morphologic and Functional Imaging, University of Messina, Messina, Italy Division of Endocrinology, Policlinico G. Martino, University of Messina, Messina, Italy

a r t i c l e

i n f o

Article history: Received 5 October 2014 Received in revised form 26 January 2015 Accepted 12 February 2015 Available online xxxx

a b s t r a c t Ureteral myxedema is exceptionally rare. We describe computed tomography and magnetic resonance imaging findings in a case of ureteral myxedema. The demonstration of water-like hyperintensity around the ureteral lumen on heavily T2-weighted sequences should be considered a strongly suggestive sign for ureteral myxedema. © 2015 Elsevier Inc. All rights reserved.

Keywords: Graves’ disease Ureteral myxedema Magnetic resonance imaging Magnetic resonance hydrography

1. Introduction Graves’ disease is an autoimmune disorder of the thyroid gland that may be associated with extrathyroidal manifestations. Among them, ophthalmopathy, present in 30% of patients, is the most common whereas dermopathy (myxedema), occurring in 1–4% of patients, and acropachy, occurring in b1% of patients, are far less common [1,2]. Ureteral myxedema represents an exceptionally rare finding since only one case has been reported in the literature [3]. We describe a case of ureteral myxedema, with emphasis on computed tomography (CT) and magnetic resonance (MR) imaging findings, in a patient with exophthalmos, dermopathy, and acropachy. 2. Case report A 56-year-old white man with a 20-year history of Graves’ disease had a presumptive diagnosis of retroperitoneal fibrosis (RPF) as an incidental finding at lumbar CT scan. The patient had a history of hyperthyroidism (treated by 131-iodine radioablative therapy), surgically treated exophthalmos (nonresponsive to 131-iodine therapy and corticosteroids), and multifocal cutaneous myxedema treated with corticosteroids. Physical examination revealed exophthalmos and yellowish brown dermal plaques affecting the dorsal aspect of both hands and the

anterior portion of the right. Radiographs of the hands showed typical findings of thyroid acropachy: lacy and asymmetric periostitis of the radial diaphyseal aspect of the first and second metacarpal bones and of the basal phalanx of the thumb [2]. CT urogram showed an 18-mm sausage-like hypodense tissue with sharp and well-defined margins, extending along the entire left ureter and renal pelvis. Excretory phase of CT urogram revealed prompt urinary excretion of contrast medium without pyeloureteral dilation (Fig. 1a). No contrast enhancement of the thickened ureter and pelvis could be seen (Fig. 1b). On MR, using a 1.5-T scanner (Signa HDxt, GE Healthcare), the tissue appeared hyperintense on T2-weighted images (half-Fourier acquisition single-shot fast spin-echo sequence; TR/TE, ∞/88 ms) (Fig. 1c and d) and on heavily T2-weighted images (2D fast spin-echo sequence; TR/TE, 2636/1393 ms) (Fig. 1e). In-phase T1-weighted images (fast gradient-echo sequence; TR/TE, 150/4.4 ms; flip angle, 80°) showed slight tissue hyperintensity (Fig. 1f), whereas opposed phase images (TR/TE, 150/2.1 ms; flip angle, 80°) revealed an evident chemical shift artifact at the interface between thickened ureter and retroperitoneal fat and signal drop within the periureteral soft tissue (Fig. 1g). A biopsy showed ureteral myxedema with abundant interstitial myxoid material. 3. Discussion

☆ Conflict of interest: None. ⁎ Corresponding author. Section of Radiological Sciences, Department of Biomedical Sciences, Morphologic and Functional Imaging, University of Messina, Italy. Tel.: + 390902212939; fax: +39-0902934847. E-mail addresses: [email protected] (F. Minutoli), [email protected] (C. Benedetto), [email protected] (C. Visalli), [email protected] (A. Granata), [email protected] (M. Gaeta).

Ureteral myxedema is a very rare condition and should be differentiated by several retroperitoneal and ureteral diseases that warrant a drastically different treatment. To the best of our knowledge, only one case of ureteral myxedema has been reported in the literature [3]: in their letter, Garcia-Arnes

http://dx.doi.org/10.1016/j.clinimag.2015.02.012 0899-7071/© 2015 Elsevier Inc. All rights reserved.

Please cite this article as: Minutoli F, et al, Computed tomography and magnetic resonance imaging findings of ureteral myxedema in Graves’ disease, Clin Imaging (2015), http://dx.doi.org/10.1016/j.clinimag.2015.02.012

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Fig. 1. (a) Paracoronal thin maximum intensity projection (MIP) from excretory phase of CT urogram showing hypoattenuating tissue (arrowheads) surrounding normal caliber ureter; there is no hydronephrosis. (b) Nephrographic phase of CT urogram axial scan showing nonenhancement of ureteral myxedema (arrow); (c) 5-mm-thick axial fat-suppressed T2-weighted half-Fourier acquisition single-shot fast spin-echo image and (d) paracoronal 12-mm-thick MIP from half-Fourier acquisition single-shot fast spin-echo sequence showing left ureteral hyperintense tissue (arrowheads); (e) paracoronal 3-cm-thick MIP from heavily T2-weighted 2D fast spin-echo showing signal intensity of the pyeloureteral tissue (arrowheads) comparable with that of cerebrospinal fluid; (f) axial in-phase image showing slightly hyperintense ureteral tissue (arrow); (g) axial opposed-phase image showing evident chemical shift artifact (arrow) at the interface between left ureter and retroperitoneal fat. Also note the presence of signal drop within the periureteral soft tissue.

et al. described a patient affected by Graves’ disease with exophthalmos and pretibial myxedema who developed myxedema of both ureters and renal pelves; they showed a coarse bilateral mildly hyperintense periureteral soft-tissue mass on short tau inversion recovery images causing bilateral hydronephrosis. Our case confirms that ureteral myxedema has to be included in the list of extrathyroidal manifestations in Graves’ disease patients. On the other hand, some imaging findings in our case are different from those previously reported; namely, our case demonstrates that ureteral myxedema may be unilateral and may not cause hydronephrosis. Diagnosis of ureteral myxedema may be postulated taking in count clinical background, morphologic findings, and MR signal intensity. The main differential diagnosis of ureteral myxedema is RPF. RPF is characterized by proliferation of aberrant fibroinflammatory tissue that usually consists of a well-delimited but irregular soft-tissue mass that surrounds the infrarenal portion of the abdominal aorta (the mass usually spares the posterior aspect of aorta and causes no aortic displacement), inferior vena cava, and iliac vessels and often (56–100% of cases of

idiopathic RPF) entraps and obstructs the ureters causing hydronephrosis [4]. RPF is frequently responsible for ureteral bowing [5]. Retroperitoneal perivascular involvement or medial deviation of the ureters is lacking in ureteral myxedema. Nevertheless, although uncommon, atypical RPF without involvement of the paraaortic area may occur representing a diagnostic challenge [4]. Lymphoma, the most common malignancy of retroperitoneum, usually shows perirenal extension, aortic displacement, and additional enlarged lymph nodes [5]. Ureteral thickening due to nonpapillary urothelial carcinomas is usually irregular with an extended, irregular ureteral stricture determining hydronephrosis [6,7]. Focal or diffuse wall thickening with intramural calcifications that often results in ureteral obstruction is the most common findings of amyloid deposition in the urinary tract [8]. Soft-tissue infiltration of renal pelvis and proximal ureter may also be present in Erdheim-Chester disease (ECD); however, in ECD patients, bone is almost always (96% of cases) affected and perirenal space is frequently involved [9]. Hyperintensity on T2-weighted sequences is an important sign of ureteral myxedema; Garcia-Arnes et al. referred it to “a large aqueous

Please cite this article as: Minutoli F, et al, Computed tomography and magnetic resonance imaging findings of ureteral myxedema in Graves’ disease, Clin Imaging (2015), http://dx.doi.org/10.1016/j.clinimag.2015.02.012

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component” of the tissue [3]. A very interesting finding in our case is hyperintensity on heavily T2-weighted images (Fig. 1e) and chemical shift artifact with the adjacent retroperitoneal fat. This finding is not surprising since it is related to high stationary water content of myxoid tissue [10,11] and can help the radiologist in addressing the diagnosis of ureteral myxedema since other diseases affecting the ureter and retroperitoneum do not usually show high signal intensity on heavily T2-weighted images. Namely, idiopathic RPF and lymphoma typically show variable signal intensity on T2-weighted images (signal intensity of RPF reflects the degree of active inflammation [4,5] and signal intensity of lymphoma seems to depend on lesion histology and localization [5]) whereas amyloid lesions are characteristically hypointense on T2weighted images [8]. Recently, a unique case of periureteral spread of a uterine leiomyoma with myxoid degeneration has been described [12]. Although CT and MR imaging features of periureteral involvement are similar to that visible in our patient in this case, the different clinical settings allow a simple differential diagnosis. Drop of signal intensity within the periureteral soft tissue, on the opposed phase images, may be related with the retention of small amounts of fat in the middle of myxedema during myxoid material accumulation process. In conclusion, diagnosis of ureteral myxedema should be considered when ureteral water-rich tissue without ureteral obstruction is found in patients with Graves’ disease. The demonstration of water-like hyperintensity around the ureteral lumen on heavily T2-weighted sequences should be considered a strongly suggestive sign.

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References [1] Schwartz KM, Fatourechi V, Ahmed DDF, Pond GR. Dermopathy of Graves’ disease (pretibial myxedema): long term outcome. J Clin Endocrinol Metabol 2002;87:438–46. [2] Fatourechi V, Ahmed DD, Schwartz KM. Thyroid acropachy: report of 40 patients treated at a single institution in a 26-year period. J Clin Endocrinol Metab 2002;87 (12):5435–41. [3] García-Arnés JA, García-Casares N, Soler J, Garin JM, Garriga MJ, Leon M. Ureteric myxoedema. A new location in Graves’ disease. Clin Endocrinol (Oxf) 2014; 80:613–20. [4] Caiafa RO, Vinuesa AS, Izquierdo RS, Brufau BP, Ayuso Colella JR, Molina CN. Retroperitoneal fibrosis: role of imaging in diagnosis and follow-up. Radiographics 2013;33(2):535–52. [5] Rosenkrantz AB, Spieler B, Seuss CR, Stifelman MD, Kim S. Utility of MRI features for differentiation of retroperitoneal fibrosis and lymphoma. AJR 2012;199(1):118–26. [6] Xu AD, Ng CS, Kamat A, Grossman HB, Dinney C, Sandler CM. Significance of upper urinary tract urothelial thickening and filling defect seen on MDCT urography in patients with a history of urothelial neoplasms. AJR 2010;195(4):959–65. [7] Blandino A, Gaeta M, Minutoli F, Salamone I, Magno C, Scribano E, Pandolfo I. MR urography of the ureter. AJR Am J Roentgenol 2002;179:1307–14. [8] Kawashima A, Alleman WG, Takahashi N, Kim B, King Jr BF, LeRoy AJ. Imaging evaluation of amyloidosis of the urinary tract and retroperitoneum. Radiographics 2011; 31(6):1569–82. [9] Antunes C, Graça B, Donato P. Thoracic, abdominal and musculoskeletal involvement in Erdheim-Chester disease: CT, MR and PET imaging findings. Insights Imaging 2014;5(4):473–82. [10] Gaeta M, Vinci S, Minutoli F, Mazziotti S, Ascenti G, Salamone I, Lamberto S, Blandino A. CT and MRI findings of mucin-containing tumors and pseudotumors of the thorax: pictorial review. Eur Radiol 2002;12(1):181–9. [11] Gaeta M, Minutoli F, Ascenti G, Vinci S, Mazziotti S, Pandolfo I, Blandino A. MR white lung sign: incidence and significance in pulmonary consolidations. J Comput Assist Tomogr 2001;25:890–6. [12] Mazziotti S, Ascenti G, Racchiusa S, Mileto A, Gaeta M. Retroperitoneal growth of degenerated myxoid uterine leiomyoma mimicking sarcoma. Clin Radiol 2012;67: 616–7.

Please cite this article as: Minutoli F, et al, Computed tomography and magnetic resonance imaging findings of ureteral myxedema in Graves’ disease, Clin Imaging (2015), http://dx.doi.org/10.1016/j.clinimag.2015.02.012

Computed tomography and magnetic resonance imaging findings of ureteral myxedema in Graves' disease.

Ureteral myxedema is exceptionally rare. We describe computed tomography and magnetic resonance imaging findings in a case of ureteral myxedema. The d...
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