Spindle epithelial tumour with thymus-like differentiation: report of two cases

Abstract

Spindle epithelial tumour with thymus-like differentiation (SETTLE) is a very rare neck malignancy arising from thymic tissue or branchial pouch, mostly seen in the early decades of life. SETTLE is thought to be a low-grade neoplasm but distant metastases have been reported. Fewer than 50 cases have been reported in the PubMed database. We report on the four-year follow-up for a 13-year-old boy, with no signs of recurrence or distant metastasis. In addition, a 45-year-old woman was admitted to hospital with neck mass. Fine-needle aspiration biopsy was compatible with medullary thyroid carcinoma but serum levels of calcitonin were normal. Total thyroidectomy and central compartment lymph node dissection was planned with an initial diagnosis of medullary thyroid carcinoma. At surgery, frozen section analysis converted our diagnosis to SETTLE and the intraoperative strategy was changed. SETTLE should be considered in a patient with normal serum calcitonin levels in the presence of suspicious medullary thyroid carcinoma at fine-needle aspiration biopsy. Frozen section analysis may help to manage the intraoperative strategy. This report describes the first case of SETTLE successfully diagnosed by frozen section analysis.

When to settle for SETTLE! A lesson learned from our cases

“…Since the tumor is generally slowly growing and indolent in nature, patients seek delayed medical attention which could result in metastasis [ 2 ]. The principal site of metastasis is lung, which represents more than 60% of the metastasis [ 33 – 35 ]. Other reported sites include mediastinum, regional lymph nodes, liver, kidney, pancreas, bone, pleura and peritoneum.…”

Spindle epithelial tumor with thymus-like differentiation: A case report and literature review*

“…In some cases, SETTLE lesions also metastasize to the lymph nodes, bones, and kidneys. Distant SETTLE metastases generally occur at a late stage, up to 25 years after the initial diagnosis [10] . Even in the presence of metastatic lesions, the patient can still survive for a long time after treatment.…”

Spindle epithelial tumor with thymus-like elements (SETTLE): A diagnostic challenge with distinct therapeutic implication; case report

“…Surgery forms the mainstay of treatment in resectable cases and nodal dissection is unwarranted in node negative cases [3]. Only 47 cases of SETTLE have been documented in indexed literature so far of which only 5 have occurred in older age group patients of more than 50 years [2,[4][5][6][7][8][9][10]. Herein, we report such a case occurring in a 56 year old lady who was treated with surgical resection and remains disease free after a period of 6 months post operatively.…”