Regional teaching for Severn deanery, June 2016
Prepared by Dr Naomi Carson, Dr Hannah Lowes and Dr Mary Brett
Proffered diagnosis was medullary thyroid carcinoma. Congo red was positive and birefringent. Calcitonin & CEA were positive, and CK19 was negative. Additional tumour foci/ C cell hyperplasia were seen elsewhere in the lobe, but C cell hyperplasia was not confirmed in the completion specimen. An incidental micropapillarythyroid carcinoma was noted. Pre-op FNA had been difficult – suspicious of papillary thyroid carcinoma, sent for external review – follicular-patterned lesion with DD including FVPTC. No mention of MTC by either. The cytology contained “thick colloid” - ?amyloid, and three dimensional groups of cells with crowded nuclei, high nuclear cytoplasmic ratios and follicular formations.
Multiple medullary microcarcinomas favoured over C-cell hyperplasia due to their number and size.
Hurthle cell carcinoma
Widely invasive Hurthle Cell carcinoma with vascular invasion. In places the tumour had a few insular areas. All members thought this was a Hurthle cell carcinoma.
*See SN13-****** (From Jan 2016 thyroid test set) FNA thyroid – Hurthle cell adenoma*
Hyalinising trabecular tumour.
Most members diagnosed a hyalinising trabecular tumour, with a few diagnoses of medullary and papillary carcinoma. This lesion had nuclear grooving and nuclear pseudoinclusions, with a vescicular chromatin pattern, without necrosis, or pleomorphism. The tumour cells were thyroglobulin, CK7, CD56, MNF116, 34BE12, and CK19+ve, and CK20, HBME1, calcitonin, chromogranin, synaptophysin and S100 –ve. MIB labelling index <1%. There was a discussion about how these lesions are currently viewed, including LiVolsi’s 3 groups, noting that cytology is often challenging and bizarre, e.g. polyhedral cells, multiple intranuclearinclusions.
*See paper: Hyalinizing trabecular tumor of the thyroid: case report and review of the literature*.
Cribriform morular variant of papillary thyroid carcinoma.
*See paper: Cribriform-morular variant of papillary thyroid carcinoma: clue to early detection of familial adenomatous polyposis-associated colon cancer*
Intra-thyroid parathyroid adenoma.
(SH11-7516 EXTRA CASE - Primary hyperparathyroidism. Imaging unclear but suggested an enlarged right sided parathyroid gland. Southmead case of intra-thyroid parathyroid with corresponding immunohistochemistry)
Water clear cell adenoma
Benign intramuscular congenital thyroid rest.
The slide circulated showed cytologically normal thyroid tissue with skeletal muscle, with no invasion of muscle or papillary cytological features. This was interpreted by the submitting pathologist as a benign intramuscular congenital thyroid rest. There was a wide range of proffered diagnoses here, and many members were concerned about follicular variant of papillary carcinoma. This lesion was thyroglobulin +ve, HBME1 –ve, and CK19+ve. Benign thyroid lesions are known to infiltrate muscle in some circumstances.
Minimally invasive follicular carcinoma in a child with PTEN mutation. Somatic PTEN mutation positive.
*See paper: Thyroid pathology findings in Cowden syndrome; a clue for the diagnosis of PTEN Hamartoma syndrome*
Subacute granulomatous thyroiditis (De Quervain’s) favoured over other causes of granulomatous thyroiditis.
*See paper: Viruses and thyroiditis*
Follicular variant papillary thyroid carcinoma
Agreement that this was an aggressive tumour, some tall cell areas. Also that any element of classical PTC would trump a diagnosis of straightforward FVPTC.
Poorly differentiated thyroid carcinoma with background FVPTC.
Range of responses, but all malignant. Vascular invasion present. Capsule invasion present. Other sections had necrosis and mitoses (not the section provided) but it shows papillary carcinoma nuclei.
For interest: Nomenclature revision for encapsulated follicular variant of papillary thyroid carcinoma. A paradigm shift to reduce overtreatment of indolent tumours.Nikiforov et al, JAMA Oncology, 2016.
Hyalinizing trabecular tumor of the thyroid: case report and review of the literature - http://www.ncbi.nlm.nih.gov/pubmed/22970009
Cribriform-morular variant of papillary thyroid carcinoma: clue to early detection of familial adenomatous polyposis-associated colon cancer - http://www.ncbi.nlm.nih.gov/pubmed/15593462
Thyroid pathology findings in Cowden syndrome; a clue for the diagnosis of PTEN Hamartoma syndrome -http://ajcp.oxfordjournals.org/content/144/2/322
Viruses and thyroiditis -http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2654877/
Nomenclature revision for encapsulated follicular variant of papillary thyroid carcinoma. A paradigm shift to reduce overtreatment of indolent tumours. Nikiforov et al, JAMA Oncology, 2016 - http://oncology.jamanetwork.com/article.aspx?articleid=2513250
Editorial on the above paper about NIFTP -http://oncology.jamanetwork.com/article.aspx?articleid=2513246
Review of papillary thyroid carcinoma -http://www.nature.com/modpathol/journal/v24/n2s/abs/modpathol2010129a.html