Carcinomas of the Thyroid with Ewing Family Tumor Elements (CEFTEs): A Diagnostic Challenge Before Surgery

Adamantinoma-Like Ewing Sarcoma of the Head and Neck: A Case-Series of a Rare and Challenging Diagnosis

Adamantinoma-like Ewing sarcoma (ALES) is a rare malignant tumor characterized by EWSR1::FLI1 related fusions and complex epithelial differentiation. ALES poses a tremendous diagnostic challenge owing to its resemblance to a wide variety of common head and neck malignancies. We aimed to study the clinicopathologic spectrum of ALES diagnosed at our institute. A retrospective review of the clinical and pathologic features of all EWSR1-rearranged ALES cases was performed after confirming the diagnosis. The cases lacking EWSR1 rearrangement were excluded. A total of 7 patients were analyzed. The median age was 27 years (range 7-42 years). There were 4 males and 3 female patients. Tumors were distributed as follows: maxilla (n = 2), parotid (n = 2), nasal cavity (n = 1), ethmoid/maxilla (n = 1), and thyroid (n = 1). Tumor size ranged from 2.2 to 5.5 cm. On microscopy, tumors displayed nested-lobular architecture, monomorphic cells, and interlobular fibrotic stroma. Other features included: palisading (n = 5), squamous differentiation (n = 2), keratinization (n = 1), colonisation of salivary ducts (n = 1) and thyroid follicles (n = 1), follicle-like cysts (n = 3), calcification (n = 2), necrosis (n = 3). Mitotic rate was 4-15/2 mm². On immunohistochemistry, cytokeratins (100%), p40 (100%), strong/diffuse membranous CD99 (100%), NKX2.2 (100%), Fli-1 (71%), and synaptophysin (71%) was positive. Patients received chemotherapy (n = 7) and radiotherapy (n = 4). Two patients developed recurrence at 6 and 10 months; 3 developed metastases at 0, 6, and 25 months. ALES is a rare and aggressive malignancy that mimics diverse neoplasms common in the head and neck region. Awareness of the morphologic and immunohistochemistry spectrum of this tumor is essential to avoid diagnostic errors.

An innovative synthetic support for immunocytochemical assessment of cytologically indeterminate (Bethesda III) thyroid nodules

BACKGROUND

Fine needle aspiration (FNA) is the procedure of choice in the evaluation of thyroid nodules. Nodules with indeterminate cytological categories, Bethesda III and IV, pose challenges in clinical practice and are frequently submitted to diagnostic surgery. CytoFoam Core (CFCS) uses an absorbent foam device inserted into the needle hub to collect the cytological sample aspirated during FNA. Specimen is formalin-fixed and paraffin-embedded.

AIM OF THE STUDY

Assessing diagnostic efficacy of CFCS, compared to traditional cytology, in re-evaluating thyroid nodules classified as Bethesda III, using post-surgical histology as reference standard.

METHOD

Retrospective study on 89 patients with a first indeterminate cytological report who were referred to the Department of Endocrinology of Regina Apostolorum Hospital (Albano L. Rome, Italy) for a second FNA. FNA was performed after at least one month under ultrasound guidance with a 23G needle according to the established procedure. During the second procedure, both traditional cytological (TC) smears and a single-pass CFCS specimen were obtained for each patient. On CFCS samples immunocytochemical staining for Galectin-3, HBME-1, and CK-19 was also performed. 51 patients eventually underwent surgery, and their histological diagnoses were compared to the TC and CFCS reports. Four parameters were evaluated: inadequacy rate, rate of persistent indeterminate (Bethesda III and IV) reports, rate of malignancy in persistently indeterminate nodules, and rate of cancer in lesions cytologically classified as malignant.

RESULTS

Non-diagnostic samples were 6 (11.8%) in TC vs 3 (5.9%) in CFCS (p=0.4). Persistent indeterminate samples were 31 (60.8%) in TC vs 19 (37.2%) in CFCS (p=0.01). Rate of malignancy in persistently indeterminate nodules was 8/19 (42.1%) in CFCS vs 9/31 (29%) in TC group (p=0.3). Nine/51 (17.6%) samples were classified as benign by TC vs 21/51 (41.2%) samples by CFCS (p<0.01). All nodules resulted benign at post-surgical evaluation. Five/51 (9.8%) samples were classified as suspicious for malignancy/malignant in TC group against 8/51 (15.7%) samples in CFCS (p=0.5). Post-surgical evaluation confirmed malignancy in all these cases.

CONCLUSION

CFCS demonstrated greater diagnostic accuracy than TC in repeat FNA assessment of cytologically indeterminate nodules. CFCS increased the conclusive diagnosis rate and decreased the number of cytologically indeterminate cases.

Improvement of the Collection, Maintenance, and Analysis of Neoplastic Cells from Urine Specimens with the Use of CytoMatrix

Urine cytology is a non-invasive test used in combination with cystoscopy for screening and follow-up of urothelial carcinoma (UC). Although cytology can be used to efficiently identify high-grade UC, it has a lower accuracy for the diagnosis of low-grade UC or patients with presence of atypical urothelial cells (AUC). For these reasons, ancillary tests have been added to urine cytology in order to improve the accuracy. However, the poor abundance of neoplastic cells in most samples and the absence of a "tissue-like" structure remains a major challenge. We used a novel synthetic support called CytoMatrix which has the property of capturing and storing cells and micro-macro aggregates within its three-dimensional structure. The urine specimens were obtained from 12 patients: 6 with suspected urothelial neoplasia (low- and high-grade) and 6 with AUC or non-neoplastic samples. The first step is the urine samples preparation, through several centrifugation passages; the second step consists in absorbing cells on the CytoMatrix, and in the subsequent formalin fixation, standard processing and paraffin embedding to prepare FFPE-CytoMatrix block. In the final step, sections are consecutively cut, stained with hematoxylin-eosin (H&E), and analyzed via UroVysion FISH and immunohistochemistry (IHC). Using our simple and reliable protocol, we can improve the quality of urine specimens, allowing a better collection, maintenance, and analysis of cells, with the advantage of using ancillary tests to support cytological diagnosis and the advantage of storing cellular material in a FFPE-CytoMatrix block.

Primary Extra-Osseous Ewing Sarcoma of the Thyroid: A Case Report and Review of the Literature

Extra-osseous Ewing sarcoma (ES) is a rare and aggressive malignant tumor found in a variety of organs. Primary ES of the thyroid is exceedingly rare and few cases have been documented to date. We describe the case of a 54-year old woman with a history of breast carcinoma in whom a unique hypermetabolic left thyroid nodule was identified during a follow-up PET-CT scan. An ultrasound examination showed a hypoechogenic nodule of 3.7 cm. A cytological diagnosis of poorly differentiated thyroid carcinoma was made, and a total thyroidectomy was performed. The surgical specimen revealed a poorly differentiated neoplasm composed of medium-sized cells with scant cytoplasm, expressing pancytokeratin, CD99 and NKX2.2 but lacking p63 and p40 expression. Molecular analysis revealed a EWSR1-FLI1 fusion transcript supporting the diagnosis of a primary extra-osseous ES of the thyroid. The patient received adjuvant chemotherapy and has no evidence of recurrent disease.

Neuroendocrine Tumors of the Thyroid and Their Mimics

This paper will review neuroendocrine lesions of the thyroid and the differential diagnosis with the most significant such tumor of the thyroid, that is, medullary thyroid carcinoma. A brief overview of the understanding of this tumor's identification as a lesion of C cells and its familial and syndromic associations will be presented. Then, a discussion of the various mimics of medullary carcinoma will be given with an approach to the types of tests that can be done to arrive at a correct diagnostic conclusion. This review will focus on practical "tips" for the practicing pathologist.

Pitfalls in Challenging Thyroid Tumors: Emphasis on Differential Diagnosis and Ancillary Biomarkers

Thyroid pathology encompasses a heterogenous group of clinicopathological entities including rare and diagnostically challenging neoplasms. The review is focused on morphological, immunohistochemical, and molecular features of rare thyroid neoplasms that can pose diagnostic problems. The tumors are organized based on growth patterns including thyroid neoplasms with predominantly papillary, follicular, solid, and spindle cell growth pattern, as well as neoplasms with distinct cytological characteristics. A special section is also dedicated to rare thyroid tumors with peculiar patterns including thyroid carcinoma with Ewing family tumor elements and intrathyroidal thymic-related neoplasms.