Nasoalveolar cyst as a cause of false positive result in post

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Rev Esp Med Nucl Imagen Mol. 2012;31(5):288–289
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Nasoalveolar cyst as a cause of false positive result in post-therapy 131 I whole
body scintigraphy夽
Quiste nasoalveolar como falso positivo en el rastreo corporal total tras dosis ablativa de131 I
P. García-Talavera a,∗ , M.Á. Ruiz a , A.A. Montes b , C. Gamazo a , M.L. González a , R. Olmos a
a
b
Servicio de Medicina Nuclear, Hospital Clínico Universitario de Valladolid, Valladolid, Spain
Servicio de Radiodiagnóstico, Hospital Comarcal de Medina del Campo, Valladolid, Spain
a r t i c l e
i n f o
Article history:
Received 20 September 2011
Accepted 12 November 2011
We present the case of a 72-year-old male who underwent thyroidectomy for encapsulated follicular carcinoma (3.5 cm × 3 cm) in
the left thyroid lobe and was referred to the Department of Nuclear
Medicine for ablation of thyroid remnants. On administration of 131 I
(3700 MBq) the TSH value was 63.8 ␮IU/ml, thyroglobulin 0.4 ng/ml
and antithyroglobulin antibodies 25.70 U/ml.
In the whole body scan (WBS) performed 8 days later two small
cervical focal uptakes were observed compatible with thyroid remnants and another deposit was found above these (Fig. 1). To better
localize the latter deposit head and neck SPECT-CT was carried out
showing that the abnormal uptake was situated in a lesion of the
right nasal fossa (Fig. 2) which was clinically, radiologically (Fig. 3)
and anatomopathologically diagnosed as a nasoalveolar cyst.
Nasoalveolar cysts are lesions of embrionary origin which
are non-odontogenic and are localized in the anterior maxillary
vestibulum. The origin of these cysts is found in the remnants of
the inferior and anterior portions of the nasolacrimal duct. Clinically they are painless swelling, generally unilateral, most of which
appear in the 4th and 5th decades of life, mainly in females.1,2
Radiologically these cysts are deep soft tissue, extraosseous lesions,
although they are rounded, well delimited and adjacent to the anterior lamina of the upper maxilla.1
Multiple causes have been described for false positive results in
the WBS with 131 I. Since the incorporation of the routine practice
of SPECT-CT studies, the diagnosis and characterization of these
false positive results has significantly improved, with their contribution having recently been reported in the case of a nasolacrimal
cyst.3 We agree that SPECT-CT allows more precise evaluation of
the focal of uptake, improving its localization. Indeed, in our case,
and in that of Mulazimoglu et al.,3 this technique was shown to be
able to exclude other more common causes of uptake such as bone
metastasis, nasal secretion, and cutaneous contamination.
Fig. 1. WBS post-ablation dose of 131 I with high energy collimators (PHILIPS, SKYLIGHT) showing two foci of cervical uptake compatible with thyroid remnants and
another of greater intensity and size in a superior localization (the uptake in the
lower left extremity was due to urinary contamination).
夽 Please cite this article as: García-Talavera P, et al. Quiste nasoalveolar como
falso positivo en el rastreo corporal total tras dosis ablativa de131 I. Rev Esp Med
Nucl Imagen Mol. 2012;31(5):288–9.
∗ Corresponding author.
E-mail address: [email protected] (P. García-Talavera).
2253-8089/$ – see front matter © 2011 Elsevier España, S.L. and SEMNIM. All rights reserved.
Documento descargado de http://www.elsevier.es el 16/11/2016. Copia para uso personal, se prohíbe la transmisión de este documento por cualquier medio o formato.
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289
Fig. 2. Fusion images (A) SPECT with 131 I (B) and CT (C) showing the abnormal focal uptake located in a lesion in the right nasal fossa.
References
1. Granell J, Calvo M, Puig A, Prieto E. Quiste nasoalveolar: características clínicopatologicas y estudio de imagen. ORL-DIPS. 2002;29:90–2.
2. Sapp JP, Eversole LR, Wysocki GP. Patología oral y maxilofacial contemporánea,
2a ed versión española de Contemporary Oral and Maxillofacial pathology. 2nd
ed. Madrid: Elsevier-Mosby; 2005. p. 63.
3. Mulazimoglu M, Koca S, Tamam MO, Uyanik, Ozpacaci T. False positive findings
in post-treatment iodine-131 whole-body scintigraphy in a nasolacrimal sac cyst,
confirmed with SPECT/CT and MRI. Clin Nucl Med. 2011;36:805–7.
Fig. 3. CT without contrast discovered a dense, rounded, well defined, soft tissue
lesion in the right nasal fossa.