RESUMO
BACKGROUND: Collision tumors of the thyroid gland are a rare entity. We present a case of a follicular variant of papillary carcinoma and squamous carcinoma in the thyroid. To the best of our knowledge, this is the first documentation of a collision tumor with a papillary carcinoma and a squamous carcinoma within the thyroid gland. The clinicopathological features and immunohistochemical profile are reported. The theories of origin, epidemiology and management are discussed with a literature review. CASE PRESENTATION: A 65 year old woman presented with a large thyroid swelling of 10 years duration and with swellings on the back and scalp which were diagnosed to be a follicular variant of papillary thyroid carcinoma with metastasis. Clinical examination, radiology and endoscopy ruled out any other abnormality of the upper aerodigestive tract. The patient was treated surgically with a total thyroidectomy with central compartment clearance and bilateral selective neck dissections. The histopathology revealed a collision tumor with components of both a follicular variant of papillary carcinoma and a squamous carcinoma. Immunohistochemical analysis confirmed the independent origin of these two primary tumors. Adjuvant radio iodine therapy directed toward the follicular derived component of the thyroid tumor and external beam radiotherapy for the squamous component was planned. CONCLUSION: Collision tumors of the thyroid gland pose a diagnostic as well as therapeutic challenge. Metastasis from distant organs and contiguous primary tumors should be excluded. The origins of squamous cancer in the thyroid gland must be established to support the true evolution of a collision tumor and to plan treatment. Treatment for collision tumors depends upon the combination of primary tumors involved and each component of the combination should be treated like an independent primary. The reporting of similar cases with longer follow-up will help define the epidemiology, biology and establish standardized protocols for treatment of these extremely rare tumors.
RESUMO
This paper studies the clinical and pathological predictors of local recurrence and disease-free survival (DFS) in patients with oral verrucous carcinoma (OVC) treated surgically, through a retrospective chart review. Three hundred and two patients with OVC were identified from January 1990 to December 2000, of which, 101 surgically treated patients who fulfilled our inclusion criteria were analyzed. A univariate analysis (UVA) of important prognostic factors, patterns of recurrence, and DFS is reported. Seventy-nine patients were male (M:F ratio, 3.6:1) and the mean age at presentation was 53.9 years (range, 23-90 years). The median follow up was 4.61 years (range, 0.51-14.3 years). The incidence of tobacco chewing, smoking, and alcohol intake was 77%, 42%, and 10%, respectively. Thirty-four patients (33.7%) had either leukoplakia or submucous fibrosis (SMF) on oral cavity examination. Early-stage tumors accounted for 39.7%; while 60.4% were late-stage tumors. On UVA, tumor location, presence of a premalignant lesion, smoking, and positive margins were statistically significant. Sixty-eight percent (19/28) recurred locally. The salvage rate for recurrent tumors was 66.7% (16/28) with a median post-recurrence survival of 16 months (range, 10-83 months). The five year DFS with surgical therapy was 77.6%. OVC has an excellent prognosis with surgical treatment. The significance of positive margins emphasizes the need for adequate surgical resection. Additionally, the presence of either leukoplakia or SMF and tumor location in the upper alveolar-palatal complex is associated with worse outcomes. Neck dissection, if considered, may be limited to a supra-omohyoid neck dissection (SOHND).