Latent childhood thyroid carcinoma in diffuse lymphocytic thyroiditis

Aggressive variants of follicular cell derived thyroid carcinoma; the so called 'real thyroid carcinomas'

The pathological diagnoses and classification schemes for thyroid carcinoma have changed over the past 20 years and continue to do so. New entities have been described and molecular analyses have suggested better characterisation and grouping of certain tumours. Because some of the lesions have been named differently by different authors, clinicians and patients may be confused as to what a specific patient's lesion represents. In this review, we discuss the thyroid tumours of follicular origin which are clinically unusual but important to recognise as their behaviour may be aggressive, they may not respond to radioiodine treatment and they may cause significant mortality. This paper describes these important but rare lesions, their pathological features, important clinicopathological correlations, molecular correlates and prognostic implications.

Prognostic Importance of Sclerosing Variant in Papillary Thyroid Carcinoma

The diffuse sclerosing variant (DSV) of papillary thyroid carcinoma is known for its high aggressiveness, high incidence of lymph node metastases, and high incidence of pulmonary metastases, and thus its consequently poorer prognosis. In this study, we undertook a retrospective analysis of papillary thyroid carcinomas to assess whether DSV can be considered a predictive factor for prognosis. We performed a retrospective evaluation of the Department's database of patients with papillary thyroid carcinoma who had undergone total thyroidectomy from January 1992 to December 2000. Group I consisted of 83 DSV patients and Group II was 168 pure papillary carcinoma (PC) patients. A significant prevalence of multinodular thyroid disorder on diagnosis was found for PC (P < 0.05), whereas with DSV, there was a significantly higher prevalence of post-thyroiditis nodular thyroid disorder than with PC (P < 0.001). The incidence of laterocervical lymph node pathology on diagnosis was significantly higher for DSV (P < 0.05). In 3.6 per cent of PC patients and 15.7 per cent of DSV patients, we observed recurrences in the regional lymph nodes (P < 0.001). We found 1.2 per cent distant metastases in PC patients and 7.2 per cent in DSV patients (P < 0.05). One PC patient (0.6%) and three DSV patients (3.6%) died of tumor-related causes (P < 0.05). Our study demonstrated that diffuse sclerosing carcinoma leads to a poorer prognosis to the extent that its classification as an autonomous clinical pathological entity is justified. In conclusion, we can state that DSV is a form of papillary thyroid tumor characterized by its higher aggressiveness, diffuse intrathyroid growth, and high incidence of lymph node and pulmonary metastasis. Ultimately, this means a poorer prognosis. In the presence of risk factors indicating a possible increase in biological aggressiveness, adequate postoperative treatment and close follow-up become essential.

Diffuse sclerosing variant of papillary thyroid carcinoma: a clinicopathologic and immunophenotypic analysis of 22 cases

BACKGROUND

The diffuse sclerosing variant of papillary thyroid carcinoma (DSV-PTC) is an uncommon tumor making up about 2% of all papillary thyroid carcinomas. Previous studies have not comprehensively evaluated these tumors in a large series of patients.

DESIGN

Twenty-two cases of DSV-PTC diagnosed between 1970 and 2000 were identified in the files of the AFIP. Histologic and immunohistochemical features were evaluated and patient follow-up was obtained.

RESULTS

The tumors affected 14 females and 8 males, aged 6 to 49 yr (mean, 18 yr), with males presenting at a mean older age than females (24 vs 14 yr). Symptoms included an enlarging mass in the thyroid, present for a mean of 9.5 mo. While a dominant tumor was identified in a single lobe, bilateral disease was common (n = 16). The dominant mass ranged in size from 1.7 to 5.8 cm in diameter (mean, 3.8 cm). Histologically, all cases demonstrated a papillary carcinoma (conventional, solid, or follicular pattern) diffusely involving the gland. Extrathyroidal extension, lymphocytic thyroiditis, squamous metaplasia, increased fibrosis/sclerosis, and psammoma bodies were present to a variable degree. Both the papillary carcinoma and squamous metaplasia cells were strongly immunoreactive with CK19, thyroglobulin, and TTF-1. An increased number of S-100 protein immunoreactive dendritic cells were recognized. p53 was increased (>15%) in the tumor cells in 12 patients, while Ki-67 was increased in the tumor cells in two patients. Perithyroidal and cervical lymph node metastasis occurred in 18 (82%) patients. All metastases demonstrated histologic features similar to the primary. Complete resection (thyroidectomy in 18 patients) with lymph node dissection, yielded a 95% 5-yr survival without evidence of disease. One patient died of disease after a malignant transformation of the squamous metaplasia into squamous cell carcinoma.

CONCLUSIONS

The recognition of DSV-PTC can be made with the following features: classic to solid foci of PTC, lymphocytic thyroiditis, squamous metaplasia, increased fibrosis, and innumerable psammoma bodies. DSV-PTC is more biologically aggressive than conventional PTC, but the patients' survival is not significantly different. This diagnosis should lead the clinician to aggressively manage these patients (thyroidectomy and lymph node dissection) in an effort to achieve an excellent long-term clinical outcome.

Follicle-derived thyroid cancer in young people: the Duke experience

Follicle-derived thyroid cancer is rare in the young. The authors examined a population with a low rate of radiation exposure and who were treated at a single institution. The records of 56 patients diagnosed before the age of 25 years were analyzed. The majority of patients presented with an asymptomatic thyroid mass. All patients were treated surgically and half received postoperative ablation with 131I. Recurrent disease was detected in 29%. The presence of local metastases at initial surgery was a predictor of recurrence. No patient presented with distant metastases and no patient died of thyroid cancer. Although radiation exposure remains a risk factor for thyroid cancer in the young, only a minority of patients with thyroid cancer have a known history of exposure. Patients who are diagnosed at a young age have a high rate of long-term recurrence, and should be followed closely throughout their lives.

Coexistent thyroiditis is associated with lower tumour stage in thyroid carcinoma

BACKGROUND

Microsatellite instability (MSI) is a new mechanism described in carcinogenesis of several tumours and seems to predispose for cancer in some chronic inflammatory diseases. As thyroiditis is thought to be both the cause and the consequence of thyroid carcinoma, it was the aim of this retrospective study to investigate the epidemiology and the influence of a coexistent thyroiditis on prognosis and clinicopathological parameters in an iodine-deficient area.

METHODS

The grade of lymphocytic infiltration (LI) of 153 thyroid carcinomas was determined in paraffin-embedded tissues: G0 = no LI, G1 = peritumoral LI, G2 = peritumoral LI with follicle, G3 = diffuse LI. A non-radioactive PCR-based screening method was used for detection of MSI.

RESULTS

Twenty-seven (17.7%) out of 153 carcinomas were accompanied by thyroiditis (G1, 16; G2, 5; G3, 6). Ten cases fulfilled the criteria necessary for diagnosing Hashimoto's thyroiditis. Nine out of 10 (90%) Hashimoto's cases and 16 out of 17 (94%) other thyroiditis cases were associated with a significantly (chi2 < 0.01) lower pT stage (pT1, pT2) than cases without thyroiditis. No statistical association was found by comparing multifocality or sclerosing variants with the grade of lymphocytic infiltration. MSI was detected neither in patients with severe inflammation nor in the absence of thyroiditis.

CONCLUSIONS

MSI does not seem to play a role in the pathogenesis of thyroid carcinoma. Coexistent thyroiditis is associated with a lower pT stage and thus could be an indicator of a better prognosis.

Carcinoma of the thyroid at a young age--a review of 23 patients

Twenty-three children and adolescents with thyroid carcinoma who were 20 years old or younger at the time of initial treatment were followed for a mean time of 9.5 years. Of the tumours, 21 were papillary and two follicular carcinomas. The majority (91%) of the 23 cases showed extra-thyroidal extension of the tumour. An association with chronic thyroiditis was observed in 30% of the cases. There was no history of irradiation of the head and neck in any patients. Relapse occurred in eight patients, lung metastases in two and local recurrences in six; one patient died from lung metastases 3 months after initial treatment. Male patients, advanced stage of tumour, less differentiated histological features and DNA aneuploidy were associated with a higher frequency of relapse. The prognosis of thyroid carcinomas in children and adolescents is not so good as is generally believed.

Diffuse sclerosing variant of papillary carcinoma of the thyroid. Clinical importance, surgical treatment, and follow-up study

A diffuse sclerosing variant is not very rare among papillary carcinomas of the thyroid when the patients are female and younger than 30 years of age. The variant is characterized by diffuse involvement of one or both thyroid lobes, with dense sclerosis, patchy lymphocytic infiltration, and abundant psammoma bodies. Controversy still exists concerning its prognosis. We reviewed our experience with 14 patients treated between 1958 and 1988. All patients were young females, their age being from 10 to 28 years with a mean of 19.6. Hashimoto's thyroiditis had been suspected in nine patients before they came to our clinic. Nowadays the diagnosis of this cancer is possible when we have this entity in mind and detect abundant psammoma bodies either by ultrasonography or by soft-tissue roentgenography of the neck. Total thyroidectomy with modified neck dissection was carried out in eight patients, subtotal thyroidectomy with neck dissection in five, and lobectomy with neck dissection in one. All of them are alive and well without distant metastasis at a mean follow-up of 16 years. Because most of the patients with this variant of papillary carcinoma are young women and the prognosis is favorable, a complete resection without causing later recurrence, but also cosmetic and complication-free surgery, should be considered.

Diffuse sclerosing variant of papillary thyroid carcinoma. A clinicopathologic study of 10 cases

The clinico-pathologic features of ten cases of the diffuse sclerosing variant (DSV) of papillary carcinoma of the thyroid (PCT) are presented and compared with those of 259 common PCT diagnosed during the same period at the Instituto Português de Oncologia (Centro de Lisboa). The primary therapeutic approach was basically the same in every case and follow-up information was obtained in every patient. DSV comprises 3.4% of our series of PCT. Patients with DSV are suggestively younger (34.7 +/- 19.9), than those with common PCT (42.3 +/- 16.1) regional lymph node metastases and distant metastases are significantly greater in DSV (100.0% and 50.0%, respectively) than in common PCT (38.6% and 14.3%, respectively). No significant differences were found between the two groups with regard to sex-ratio, extrathyroid invasion and mortality rate. No differences were either found regarding the immunohistochemical results: neoplastic cells of both groups showed immunoreactivity with antisera for thyroglobulin, epidermal keratins, S-100 protein and NSE. Some foci of three DSV cases displayed histological and histochemical features resembling those of the so-called mucoepidermoid carcinoma. It is concluded that a) DSV is an exceptional example of PCT in which most of the usual morphologic features of this type of carcinoma are overexpressed; b) DSV is not exclusively found in young patients and, in older patients, merges with other variants of PCT; c) DSV is indeed a more aggressive tumor than common PCT and should therefore be treated accordingly regardless of the age of the patients.

Lymphocytic infiltration in juvenile thyroid carcinoma

In this study, the significance of lymphocytic infiltration in juvenile thyroid carcinoma is clarified. We examined nine patients younger than 20 years of age. Histopathologically, there was good correlation between lymphocytic infiltration and the development and spread of carcinoma. It is believed that lymphocytic infiltration around the tumor is an immunologic reaction induced by antigens from the carcinoma itself, and also that the reaction may progress according to tumor development. Immunocytochemically, we determined what type of inflammatory cells infiltrated the thyroid and demonstrated HLA-DR expression in the cancer cells. These findings are similar to autoimmune thyroiditis in which antibody-dependent cellular cytotoxicity (ADCC) works as a main immunomechanism.