Intrathoracic stomach mimicking bone metastasis from thyroid cancer in whole-body iodine-131 scan diagnosed by SPECT/CT

Francisco Javier García-Gómez Pablo Antonio de la Riva-Pérez Cinta Calvo-Morón Cristina Buján-Lloret Teresa Cambil-Molina Juan Castro-Montaño About the authors

SUMMARY

The whole-body iodine-131 scintigraphy is an imaging technique in monitoring patients with a history of thyroid cancer. Although the rate of false positives is negligible, it is not nonexistent. We report the case of an intervened and treated patient for thyroid cancer with good clinical and biochemical response. Scintigraphic findings were consistent with unsuspected bone metastasis. Fused SPECT/CT data allowed accurate diagnosis of giant diaphragmatic hernia associated with intrathoracic stomach, a very rare pathology that can lead to false positive results.

CASE REPORT

We report a 76 year old female with history of T1N0M0 well differentiated papillary thyroid cancer being operated and treated with ablative dose of iodine-131 (131I). During regular follow-up, a whole-body 131I scintigraphy was performed 12 months after treatment ends in order to evaluate the persistence of thyroid remainders. Whole-body 131I scan (Figure 1) revealed high intense hypermetabolic uptake foci, located in the midline. This finding was observed with greater intensity of uptake in the posterior projection (Figure 1, right panel; black arrow) being consistent with disease progression as spine bone metastasis. Intense back pain was referred when the patient was purposely questioned. Hormone levels at moment of scan were stimulated Tg < 0.2 ngr/mL, nonstimulated Tg < 0.2 ngr/mL and antithyroglobulin antibodies (TgAB) 349.4 U/L (Reference range: 0.0-200.0 U/L).

Figure 1
Whole-body iodine-131 scintigraphy. 150 x 252 mm (96 x 96 DPI).

Subsequently, a single photon emission computed tomography/computed tomography (SPECT/CT) was performed due to discordance between biochemical findings (low hormone levels) and the clinical picture of intense back pain and functional imaging consistent with spine bone metastasis. A severe thoracolumbar scoliosis that determines a giant diaphragmatic hernia was revealed thanks to multimodality scan (Figure 2). Thereby, high intense hypermetabolic foci corresponded to physiological activity of the improperly positioned gastric mucosa mimicking bone metastasis.

Figure 2
Axial, sagittal and coronal views (left, center and right columns) of hydrib iodine-131 SPECT/CT. Fused images are exposed in the upper row, the SPECT alone in the center row and CT alone in the lower row. 88 x 60 mm (300 x 300 DPI).

DISCUSSION

The giant diaphragmatic hernia associated with intrathoracic stomach is a very rare entity (11. Grazia KJA, Godoy ZM, Cavallo BI, Cortés AC. Hernia hiatal gigante con estómago intratorácico: Reporte de un caso y revisión de la literatura. Rev Chil Radiol. 2012;18:179-83.) that seems to be related to increased intra-abdominal pressure and diaphragmatic laxity or kyphoscoliosis deviation in obese patients (22. Schuchert MJ, Adusumilli PS, Cook CC, Colovos C, Kilic A, Nason KS, et al. The impact of scoliosis among patients with giant paraesophageal hernia. J Gastrointest Surg. 2011;15:23-8.). Usually it corresponds to a type III hiatal hernia, with both sliding and paraesophageal components, wherein at least 30% of the stomach is in intrathoracic situation (33. Mitiek MO, Andrade RS. Giant hiatal hernia. Ann Thorac Surg. 2010;89:S2168-73.). Diaphragmatic hernias remain a diagnostic and surgical challenge, in which imaging techniques have become the cornerstone.

In another vein, whole-body 131I scintigraphy has proven to be a minimally invasive and safe technique that allows the diagnosis metastasis and recurrence after thyroidectomy when performed at 6-12 months of thyroid remainders ablation with radioiodine, as well as in monitoring during the long-term follow-up. However, the ATA and ETA guidelines state that low-risk individuals who have had a first post-radioactive iodine remnant ablation whole-body scan with an undetectable Tg level and a negative anti-Tg antibody level as well as a negative neck ultrasound do not require routine follow-up whole-body scan. Even if false positives in 131I body scans are extremely rare, they have been reported due to contamination by body fluids, ectopic thyroid tissue, infectious and inflammatory processes, benign and malignant tumors, serous cysts and even pulmonary bronchiolitis (44. García Alonso MP, Balsa Bretón MA, Paniagua Correa C, Castillejos Rodríguez L, Penín González FJ, Elviro Peña R, et al. Iodine uptake in the chest in the follow-up of well-differentiated thyroid cancer. Rev Esp Med Nucl. 2011;30:24-8.,55. Thientunyakit T. False-positive 131I whole-body scan in well-differenciated thyroid cáncer patient with respiratory bronchiolitis. Clin Nucl Med. 2013;38:730-4.). Few cases of false negatives by intrathoracic hernia have been described, because the strange location of the physiological uptake of radioiodine by the gastric mucosa and the limited resolution of planar imaging may suggest that results from a recurrence of the disease (66. Ho Y, Hicks R. Hiatus hernia: a potential cause of false-positive iodine-131 scan in thyroid carcinoma. Clin Nucl Med. 1998;23:621-2.

7. Schneider JA, Divgi CR, Scott AM, Macapinlac HA, Sonenberg M, Goldsmith SJ, et al. Hiatal hernia on whole-body radioiodine survey mimicking metastatic thyroid cancer. Clin Nucl Med. 1993;18:751-3.

8. Lee YS, Ryu YH, Chang HS, Park CS. Hiatal hernia detected by iodine-131 scan for ablation of thyroid carcinoma. ANZ J Surg. 2010;80:198.

9. Ceylan Gunay E, Erdogan A. Mediastinal radioiodine uptake due to hiatal hernia: a false-positive reason in 131I scan. Rev Esp Med Nucl. 2010;29:95.
-1010. Willis LL, Cowan RJ. Mediastinal uptake of I-131 in a hiatal hernia mimicking recurrence of papillary thyroid carcinoma. Clin Nucl Med. 1993;18:961-3.). It can also be seen in healthy tissue, such as thymus, breast, liver and gastrointestinal tract (1111. Oh JR, Ahn BC. False-positive uptake on radioiodine whole-body scintigraphy: physiologic and pathologic variants unrelated to thyroid cancer. Am J Nucl Med Mol Imaging. 2012;2:362-85.) being able to be causes of false positive (1212. Buton L, Morel O, Gault P, Illouz F, Rodien P, Rohmer V. False-positive iodine-131 whole-body scan findings in patients with differentiated thyroid carcinoma: report of 11 cases and review of the literature. Ann Endocrinol (Paris). 2013;74:221-30.).

In this case, 131I SPECT/CT allowed reaching an accurate diagnosis, by discarding unsuspected metastatic bone disease and changing significantly the management and prognosis of the patient. Laparotomy or laparoscopic surgical repair is still the treatment of choice for giant hiatal hernia (1313. Zhou Y, Du H, Che G. Giant congenital diaphragmatic hernia in an adult. J Cardiothorac Surg. 2014;9:31.).

Imaging findings

Whole-body scintigraphy after intravenous injection of 187 MBq (5 mCi) of 131I (Figure 1) demonstrated physiological uptake of the radiotracer as well as a pathological uptake deposit which was located in the midline. This finding was present in both anterior and posterior projections, presenting much greater intensity in the latter (black arrow). Due to lack of precise anatomical definition of this technique, it was compatible with spinal bone metastases as a result of the central location, greater in backplanes and high intensity of uptake.

A 131I SPECT/CT (128x128 matrix; step and shoot mode; 360 degrees orbit; 25 seconds per image; low-dose CT: 140 kV, 2.5 mA) was performed in order to clarifying our clinical and radiological inconsistency. Fused images, SPECT alone and CT alone (top-down, respectively) revealed severe kyphoscoliosis associated with giant diaphragmatic hernia and intrathoracic stomach. In this way, hypermetabolic foci corresponded to physiological radiotracer uptake of the gastric mucosa.

It is known that SPECT/CT was highly accurate in patients who underwent a single challenge of radioiodine therapy (99. Ceylan Gunay E, Erdogan A. Mediastinal radioiodine uptake due to hiatal hernia: a false-positive reason in 131I scan. Rev Esp Med Nucl. 2010;29:95.). In our case, SPECT/CT helped clarify our diagnostic doubt and substantially modified the management and prognosis of the patient.

REFERENCES

  • 1
    Grazia KJA, Godoy ZM, Cavallo BI, Cortés AC. Hernia hiatal gigante con estómago intratorácico: Reporte de un caso y revisión de la literatura. Rev Chil Radiol. 2012;18:179-83.
  • 2
    Schuchert MJ, Adusumilli PS, Cook CC, Colovos C, Kilic A, Nason KS, et al. The impact of scoliosis among patients with giant paraesophageal hernia. J Gastrointest Surg. 2011;15:23-8.
  • 3
    Mitiek MO, Andrade RS. Giant hiatal hernia. Ann Thorac Surg. 2010;89:S2168-73.
  • 4
    García Alonso MP, Balsa Bretón MA, Paniagua Correa C, Castillejos Rodríguez L, Penín González FJ, Elviro Peña R, et al. Iodine uptake in the chest in the follow-up of well-differentiated thyroid cancer. Rev Esp Med Nucl. 2011;30:24-8.
  • 5
    Thientunyakit T. False-positive 131I whole-body scan in well-differenciated thyroid cáncer patient with respiratory bronchiolitis. Clin Nucl Med. 2013;38:730-4.
  • 6
    Ho Y, Hicks R. Hiatus hernia: a potential cause of false-positive iodine-131 scan in thyroid carcinoma. Clin Nucl Med. 1998;23:621-2.
  • 7
    Schneider JA, Divgi CR, Scott AM, Macapinlac HA, Sonenberg M, Goldsmith SJ, et al. Hiatal hernia on whole-body radioiodine survey mimicking metastatic thyroid cancer. Clin Nucl Med. 1993;18:751-3.
  • 8
    Lee YS, Ryu YH, Chang HS, Park CS. Hiatal hernia detected by iodine-131 scan for ablation of thyroid carcinoma. ANZ J Surg. 2010;80:198.
  • 9
    Ceylan Gunay E, Erdogan A. Mediastinal radioiodine uptake due to hiatal hernia: a false-positive reason in 131I scan. Rev Esp Med Nucl. 2010;29:95.
  • 10
    Willis LL, Cowan RJ. Mediastinal uptake of I-131 in a hiatal hernia mimicking recurrence of papillary thyroid carcinoma. Clin Nucl Med. 1993;18:961-3.
  • 11
    Oh JR, Ahn BC. False-positive uptake on radioiodine whole-body scintigraphy: physiologic and pathologic variants unrelated to thyroid cancer. Am J Nucl Med Mol Imaging. 2012;2:362-85.
  • 12
    Buton L, Morel O, Gault P, Illouz F, Rodien P, Rohmer V. False-positive iodine-131 whole-body scan findings in patients with differentiated thyroid carcinoma: report of 11 cases and review of the literature. Ann Endocrinol (Paris). 2013;74:221-30.
  • 13
    Zhou Y, Du H, Che G. Giant congenital diaphragmatic hernia in an adult. J Cardiothorac Surg. 2014;9:31.

Publication Dates

  • Publication in this collection
    13 Feb 2017
  • Date of issue
    May-Jun 2017

History

  • Received
    Jan 2016
  • Accepted
    Oct 2016
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