Hürthle cell carcinomas are heterogeneous neoplasms that display a wide range of biological behaviour and accounts for less than 5% of all differentiated thyroid malignancies. The term HCC should be restricted to tumours with more than 75% of oncocytic cells [2
]. Oncocytes are seen in follicular thyroid cell carcinoma and in papillary thyroid cell carcinoma [13
]. On one hand patients with HCC live for years with slow growing tumour and lymphatic metastases and on the other hand, patients die of highly aggressive tumour with haematogenous spread.
Our patient had several indicators for poor prognosis such as his advanced age, male gender, large tumour size (8 cm), extra thyroid extension and nodal metastasis. Interestingly enough the patient had no pressure symptoms despite marked deviation of larynx, trachea and oesophagus, which may be due to previous right hemithyroidectomy. In elderly patients with sudden enlargement of neck mass and pre-existing thyroid conditions such as benign thyroid nodule, goitre (as in our case), Grave's disease or differentiated thyroid carcinoma, one has to bear in mind anaplastic thyroid carcinoma (ATC). In ATC local compression symptoms such as hoarseness, strider, dyspnoea and dysphagia occur as a rule [15
]. In aggressive type of HCC haematogenous spread has been noted, but in ATC, at presentation patients are quite likely to have distant metastases involving lung, bone, brain and soft tissues [15
Our patient had undergone fine needle aspiration cytology, which revealed Hürthle cells. Since the lesion was rapidly growing with mediastinal extension and nodal involvement, the patient underwent staging and left hemithyroidectomy with modified neck dissection. Histology confirmed HCC based on vascular and capsular invasion. Intraoperative frozen sections have low predictive value and are particularly not a sensitive test for diagnosing HCC therefore this was not carried out [10
]. McIvor et al have clearly shown that FNAC can easily recognise the tumour as Hürthle cell lesion [9
]. Cases with suspicious histology and over 50 years of age carry a high risk of cancer [18
In the management of HCC the primary mode of treatment is surgical, ranging from hemithyroidectomy to total thyroidectomy. Larger tumours (>T2) require total thyroidectomy and lymphadenectomy if lymph nodes are involved [8
]. Adjuvant radioiodine treatment or external beam radiotherapy is used for widely invasive carcinoma or locally advanced disease [8
Several reports in literature have identified contra lateral foci of carcinoma in 40–70% of cases of HCC [11
]. HCC is less responsive to radioactive iodine therapy [20
] and taking into account the aggressive behaviour, it has been suggested that every Hürthle cell tumour greater than 2 cm should be treated by total thyroidectomy [21
]. In 1990 they showed that recurrent disease was noted in 17% of patients treated with total thyroidectomy compared to 59% in cases where a more limited procedure was carried out [21
]. Other authors support the role of total thyroidectomy as there is 15 to 35% incidence of multiple foci in HCC [23
There are several reasons favouring the use of 131
I remnant ablation after near-total thyroidectomy [24
]. First, presence of thyroid remnant can obscure 131
I uptake in cervical or lung metastases [25
]. Second, distant (lung) metastases may be seen only on the post treatment whole body scan after remnant ablation [27
]. Finally, remnant ablation may destroy residual normal follicular cells, which may become malignant [28
] and any occult cancer that may recur years later.
Radioiodine therapy has no overall effect on mortality but subgroup analysis has shown that those patients who receive radioactive iodine for adjuvant ablation of remnant thyroid tissue have lower mortality rate compared with patients who either did not receive treatment or in whom the indication was the presence of residual disease [29
]. Radioiodine uptake in the elderly is much lower. Schlumberger and colleagues noted 131
I uptake at metastatic sites in only 53% of patients over 40 years of age, compared to 90% in patients below the age of 40 [30
]. Univariate analysis indicated that older age and large tumour size predicted worse survival rates due to aggressive nature of the tumour (extra glandular invasion and multifocal disease). One recent series reviewed medical records of patients between the years 1944 and 1995. Of the 89 HCC cases studied, 29% had only undergone lobectomy as initial treatment and 50% had undergone partial resection. Of the three quarters of the patients in this series who received radioactive iodine, only 38% of patients with known metastases showed positive uptake [29
]. Another study clearly suggested that treatment with 131
I to ablate the thyroid remnant and to treat residual disease were independent prognostic variables that favourably influenced recurrence, distant recurrence, and cancer death rates [24
]. Our patient received radioactive iodine treatment in the postoperative period. He has been followed up with whole body scans (Fig and ), which indicate his response to adjuvant radioactive iodine therapy. He is on 125 mcg thyroxine in order to maintain a TSH level of less than 0.01 mIU/L and FT4 at the upper limit of normal (8–28 pmol/L).
Whole body scan on November 3, 2003 following 131I ablation therapy on 28th October 2003, with 3060 MBq Sodium Iodine (131I). Increased uptake is seen in the region of the thyroid bed. No abnormal accumulation was noted elsewhere.
Figure 6 Whole body scan on 19th April 2004 following 131I ablation therapy on 13th April 2004 with 5911 MBq Sodium Iodine (131I). Two small focal area of uptake are seen in the thyroid bed. Low uptake focal area in the left lateral aspect of the neck, could possibly (more ...)
Stojdinovic et al
have treated 56 patients with HCC between the years 1940 and 2000 [8
]. Of these patients 23(41%) had minimally invasive disease with no evidence of extra thyroid invasion (T2 N0 M0) and 33(56%) had widely invasive HCC. Primary mode of treatment was surgery ranging from lobectomy and isthumusectomy to total thyroidectomy with cervical lymphadenectomy in presence of lymph node involvement. Some patients received adjuvant radioiodine or external beam radiotherapy for widely invasive carcinoma. Study end points were relapse free survival and disease specific survival. They reported 8 years survival rate of 100% and 58% for low and high-risk cancers respectively. In their entire study cohort age was not found to predict the outcome but the most significant factor was widely invasive carcinoma.
Khafif et al
in their series (42 patients with HCC between 1957–1997) used radioiodine in patients with distant metastases; none had thyroid remnant ablation with radioactive iodine [4
]. They reported an overall survival rate of 90.5% and noted that age, size of tumour and extent of resection adversely affected the prognosis.
Hürthle cell lesion can be easily picked up on FNAC but to make a diagnosis of HCC one has to demonstrate vascular or capsular invasion. Intraoperative frozen sections have low predictive value and cases with advanced age (over 50), rapid enlargement of lump and palpable nodes should be regarded with high index of suspicion for presence of HCC. HCC or other differentiated carcinomas of thyroid in the elderly patients are generally more aggressive with less favourable prognosis compared to younger patients. They should be offered total thyroidectomy and selective lymph node dissection (when lymph nodes are involved) followed by ablative radioiodine therapy, provided they can withstand the above treatment. Coexisting medical disorders should be recognized and managed effectively prior to surgery [31
]. Further research is needed to clarify the role of adjuvant radioiodine therapy in the management of HCC.