endocrine

Question 1

Gross and Micro features of Hashimoto

Answer 1

Gross - diffuse symmetric enlargement with bosselated or irregular surfaces and prominent pyramidal lobe, 2 -3x size of normal, weighing up to 200g

Micro
lymphoplasmacytic infiltrate with prominent germinal centres
thyroid follicles are atrophic with fibrotic background
interfollicular/interlobular fibrosis and scar storiform fibrosis
squamous metaplasia of follicles

DDx
Riedel thyroiditis - DDx for fibrous variant of HT, another candidate for IgG4 related thyroiditis, RT has more prominent obliteration follicles and extension to adjacent anatomical structures
Thyroid carcinoma
Grave’s disease - has less inflammatory infiltrate and rare oncocytic metaplasia.

Question 2

which cell type is thyroid medullary carcinoma derived? Other clinical features, gross and micro features.

Answer 2

C-cell, c-cell hyperplasia is a precursor lesion
gain of function - serum calcitonin and CEA level are elevated
cervical lymph node metastasis in 50%

sporadic in 5-6th decade
familial - 3rd decade, MEN2A-late adolescence
MEN2B- infant to early childhood

gross - unilateral solitary
familial are multifocal and bilateral
well defined, poorly formed capsule with infiltration
Tan yellow, white to light gray
firm rubbery rarely soft
gritty - finely granular calcifications
haemorrhage or necrosis usually absent

Micro
solid, nests, hyalinised fibrovascular stroma
lobular, organoid, nested, inuslar, travecular, curvilinear anatomosing cells
amylid stromal acculartion - homogenous acellular eosinphilic extracellular matrix
ceels - round, oval spindled plasmacytoid or polyhedral
round to oval nuclei stippled fine uniform salt and pepper nuclear chormatin
intranuclear cytoplasmic inclusions
mild to moderate pelomorphism
intracytoplasmic mucinous vacuoles with extracellular mucin
infrequent mitoses
necrosis uncommon
significant LVI
extensive invasion
metastasise to lymph nodes

Question 3

features of undifferentiated (anaplstic) carcinoma

Answer 3

History
>65yo
previous benign / malignant thyroid disease
rapidly expanding mass

Gross
fleshy, firm mass, typically completely replacing thyroid

Micro
Extrathyroidal extension
LVI, necrosis, haemorrhage
variety of architecture- sheet, storiform, fascicular, angiomatoid, meningothelial
poorly differentiated cells, polygonal, pleomorphic, spindle, giant cell, epithelioid, squamoid,
profound pleomorphic
mitoses

IPx
CK, Pax-8 positive in 80% cases
Thyroglobulin and TTF-1 are lost

DDx: metastasis, sarcoma, melanoma, lymphoma, primary carcinoma, IgG4+ sclerosing disease

Question 4

Diagnostic criteria of a (NIFTP) Non-invasive follicular thyroid neoplasm with papillary-like nuclear features

Answer 4

1 encapsulation / demarcation
2 follicular growth pattern, less than 1% papillae, no psammoma bodies, less 30% solid, trabecular or insular growth pattern
2 nuclear features of papillary carcinoma (nuclear score of 2-3)
4 no LVI or capsular invasion
5 no tumour necrosis
6 no high mitotic activity (less the 3 mitosis per 10 HPF)