Egyptian Journal of Ear, Nose, Throat and Allied Sciences (2013) 14, 37–40

Egyptian Society of Ear, Nose, Throat and Allied Sciences

Egyptian Journal of Ear, Nose, Throat and Allied

Sciences

www.ejentas.com

An unusual presentation of the TENIS syndrome

Y.A. Onimode a,*, A.B. Rahmani b, M.D.T. Vangu b

a Department of Nuclear Medicine, University College Hospital & Department of Radiotherapy, University of Ibadan,Oyo State, Nigeriab Department of Nuclear Medicine, CM Johannesburg Academic Hospital & University of the Witwatersrand, Johannesburg,South Africa

Received 18 October 2012; accepted 2 November 2012Available online 28 December 2012

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KEYWORDS

TENIS syndrome;

Thyroid carcinoma;

Thyroglobulin;

FDG PET/CT

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Abstract Introduction: Papillary carcinoma is the commonest subtype of thyroid cancer. Patients

are treated with radioactive iodine (RAI), and monitored with RAI scans, serum thyroglobulin lev-

els, and cervical ultrasonography. Elevated serum thyroglobulin despite a negative RAI scan is

termed the TENIS syndrome (Truncated Expression of the NIS; NIS represents the sodium-iodide

symporter). Alternative imaging is then indicated.

Method/Result: A female Caucasian patient with papillary thyroid carcinoma had been followed

up at our Thyroid Cancer clinic. A diagnostic scan revealed residual thyroid tissue. RAI ablation of

the thyroid remnant was performed with 80 mCi of RAI. Two- and five-year follow-up scans were

clear. However, thyroglobulin levels remained high, thus a diagnosis of TENIS syndrome was

made.

An F-18 FDG PET/CT scan was performed which demonstrated inhomogeneous liver uptake

(SUV > 6). Abdominal CT confirmed multiple liver lesions; ultrasound-guided FNA of these

revealed several groups of malignant cells.

Conclusion: Persistently elevated thyroglobulin levels in the presence of a negative whole-body

RAI scan are of great concern. In this patient with unusual liver metastases from papillary thyroid

cancer, and relatively low thyroglobulin levels despite significant metastases, F-18 FDG PET/CT

has once more proved its efficacy in the evaluation of patients with the TENIS syndrome.ª 2012 Egyptian Society of Ear, Nose, Throat and Allied Sciences.

Production and hosting by Elsevier B.V. All rights reserved.

artment of Nuclear Medicine,

llege Hospital, Ibadan, Oyo

.(Y.A. Onimode).

yptian Society of Ear, Nose,

g by Elsevier

ar, Nose, Throat and Allied Scien

1.002

1. Introduction

Thyroid carcinoma, though a rare tumour in the setting of gen-eral oncology, is the commonest endocrine tumour (90%), and

papillary carcinoma is its commonest subtype (70–80%) in io-dine-replete populations.1,2 It is commoner in females (M:F ra-tio of 3:1) and has a peak age incidence of 30–50 years.

Papillary thyroid carcinoma typically spreads to locoregionallymph nodes and to the lungs.

ces. Production and hosting by Elsevier B.V. All rights reserved.

Figure 1 Whole-body radioiodine-131 scan.

38 Y.A. Onimode et al.

Following total thyroidectomy and radioactive iodine abla-tion, patients are monitored with whole-body iodine scans and

serum thyroglobulin levels.3 In this setting, thyroglobulin is asensitive tumour marker, even more under so the stimulationof thyroid stimulating hormone (TSH) (98% compared to80% under TSH suppression).4,5 A varying proportion of pa-

Table 1 Thyroglobulin, antithyroglobulin antibody and thyroid ho

Tg* (ng/ml) Anti-Tg Antibody (ng/m

On T4 suppression 0.5 <10.0

Off T4 suppression 10 10

* Tg: Thyroglobulin.** TSH: thyroid stimulating hormone.

Figure 2 Hepatic metastases as seen on

tients (up to 56%)6–9 may exhibit elevation of thyroglobulin inthe presence of a negative I-131 whole-body scan. This condi-tion has been termed the TENIS syndrome (Truncated Expres-

sion of the NIS, NIS being an acronym for the sodium-iodidesymporter). The syndrome has been attributed to several pos-sible aetiologies, such as small dose of radioiodine used for the

diagnostic scan, ‘‘stunning’’ of radioiodine (RAI) uptake byfunctional thyroid tissue, dedifferentiation of the carcinoma,loss of function mutation of the NIS, iodine ingestion/admin-

istration blocking RAI uptake, absence of immunoreactivecytoplasmic thyroglobulin and thyroxine,10,11 or to tumoursize below gamma camera resolution.12 When compared toother alternative imaging agents, F-18 FDG PET/CT imaging,

with a sensitivity of 85–94% and a specificity of 90–95%,13 hasbeen declared by a consensus as the most suitable modality fordetecting tumour spread and recurrence in such instances. This

claim is substantiated by other studies.14,15 It was also ob-served that the sensitivity of FDG PET imaging increased inpatients with the TENIS syndrome.16,17

2. Method/case report

A 41 year old female patient known with papillary thyroid

carcinoma had been followed up at our thyroid cancer clinic.Following completion thyroidectomy, she had a diagnosticradioiodine scan, which revealed the presence of residual

thyroid tissue. RAI ablation of the thyroid remnant was per-formed with 80 mCi I-131 in December 2000. The patient then

rmone assays at 5th year follow-up.

l) T4 (pmol/L) T3 (pmol//L) **TSH (mIU/L)

19.5 4.3 0.3

2.6 0.7 36.54

patient’s F-18 FDG PET/CT scan.

Figure 3 Inhomogeneous hepatic metastases as seen on transaxial slices of (A) F-18 FDG PET, (B) CT and (C) fused PET/CT scan.

An unusual presentation of the TENIS syndrome 39

underwent follow-up scans at 6 months, 1 year, 2 yearsand 5 years afterwards, which were all clear (see 5-year

scan, Fig. 1). However, a sudden increase in the thyroglobu-lin (Tg) levels was noted at her five-year follow-up (Table 1);the patient was thus diagnosed as having the TENIS

syndrome.

3. Result

PET/CT imaging (Figs. 2 and 3) demonstrated inhomogeneousuptake in the liver, with focal increased activity in the rightlobe; in segments 4a, 5 and 8 (SUV 6.73). It also showed a

pedunculated inhomogeneous mass arising from segment 5of the liver (SUV 5.09). Abdominal CT scan findings wereconsistent with multiple liver lesions. Ultrasound-guided

FNA biopsy of the liver metastases revealed several groupsof malignant cells compatible with metastatic papillary thyroidcarcinoma. The patient was counselled regarding her prognosisand maintained on L-thyroxine 150 lg daily.

4. Conclusion

Serum thyroglobulin is an established tumour marker for mon-itoring papillary thyroid carcinoma, after total thyroidectomyand lymph node clearance. Persistently elevated thyroglobulinlevels in the presence of a negative whole-body RAI scan are of

great concern. In this patient with unusual liver metastasesfrom papillary thyroid cancer, and relatively low thyroglobulinlevels despite significant metastases, F-18 FDG PET/CT has

once more proved its efficacy for further evaluation of patientswith the TENIS syndrome.

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