Cytologic findings of spindle epithelial tumor with thymus‐like elements

Abstract

Spindle epithelial tumor with thymus-like elements (SETTLE) is a rare and morphologically unique biphasic pediatric thyroid tumor of low malignant potential. There are less than 50 cases reported in the literature and few reported metastases. Despite the common usage of needle aspiration for thyroid and lymph node evaluation, cytologic descriptions of SETTLE are rare and tend to focus on a hypercellular biphasic appearance. We report aspirate findings of early cystic lymph node metastases in a 14-year-old girl, showing abundant matrix and low cellularity. We propose that the lack of recognition of this abundant matrix and cystic ultrasound appearance (as well as rarity of this tumor) may account for the low number of cytologic descriptions in the literature. Improved recognition may lead to increased usefulness of aspiration in the diagnosis and follow-up of SETTLE. Laryngoscope, 128:E78-E82, 2018.

Spindle epithelial tumour with thymus‐like elements presenting with lymph node metastasis: An illustrative case report with review of literature

“…Limited cytomorphological reports of SETTLE describe cellular spindle cell fragments, loose clusters of epithelioid cells with granular, fragile cytoplasm and bare tumour nuclei (probably representative of the epithelial component), thin mucinous extracellular material, and fragments of metachromatic basement membrane‐like extracellular matrix . In our case, we also observed branching tubule‐like structures, a striking admixture of normal thyroid follicular cells and thick colloid in the background, and many spindle cells forming rosettes with central basement membrane‐like material, also depicted in the cytology microphotographs of a published case of SETTLE .…”

“…Our patient is the fifth case of SETTLE presenting with lymph node metastasis, with long‐term outcomes documented in only two previously . As exemplified by these cases (Table ), lymphatic/haematogenous dissemination probably occurs early in the course of SETTLE, and tumour circumscription, histological grade or mitoses do not appear to influence the outcome .…”

Cytomorphology of monomorphic spindle epithelial tumor with thymus‐like elements: A case with local recurrence after subtotal resection

“…Moreover, molecular rearrangement testing for SS18/SSX by FISH yielded negative results in all cases tested. For a detailed overview, please refer to Table 1 5,7,9,11‐18 …”

“…For a detailed overview, please refer to Table 1. 5,7,9,[11][12][13][14][15][16][17][18] Lastly, in the report of the prior resection (hemithyroidectomy), the tumor involved the surgical margins and had focal areas that were suspicious for lymphatic invasion. No lymph nodes were identified and post-operative imaging showed no evidence of metastatic disease and normal thyroid function tests.…”

Synovial sarcoma masquerading as medullary thyroid carcinoma

“…Lower nuclear grade, stromal hyalinisation, glomeruloid glandular structures, absence of intraglandular necrotic debris and mast cells, diffuse expression of high‐molecular weight cytokeratin and at molecular level lack of t(X;18) are useful in differentiation from SS . On cytology, lack of atypia, apoptosis and necrosis, presence of abundant matrix and a cystic ultrasound appearance are helpful features …”