CASE N°43 – Medullary thyroid carcinoma

Clinical History:

Age: 65

Sex: Male

Single thyroid nodule; Ultrasound: hypocaptation; scintigraphy: cold; serum calcitonin: 40

Cytological Image:

cytological speciemen: thyroid fine-needle aspiration

compositi cito

Cytological Report:

Aggregates composed by cells in part with eccentric nucleus and finely granular chromatin, mixed with red blood cells and scant colloid.
The cytological findings is attributable to a neuroendocrine tumor; this figure and the value of calcitonin, suggest medullary carcinoma of the thyroid.

Histological Image:

histological speciemen: thyroid, excision

compositi isto 25-8-14

Histological Report:

Medullary carcinoma of the thyroid.
Tumor growth fraction (MIB1): <5%.
The lesion appear to be limited to the context of the thyroid parenchyma.
Absence permeation of tumor vessels.

Discussions:

Unlike most other carcinomas arising from the follicular cell of

the thyroid, medullary thyroid carcinoma (MTC) is a malignancy

with neuroendocrine features, derived from the parafollicular C

cell, which is of ectodermal neural crest origin. In most studies,

MTC represents 3–12% of thyroid cancers, the majority of which

are sporadic. However, in approximately 25–30% of cases, MTC is

inherited, and is associated with one of three familial syndromes:

multiple endocrine neoplasia (MEN) syndrome type 2A, MEN

type 2B, and familial MTC.

 

Major cytologic features of medullary carcinoma are as follows:

• Uniform population of single cells

• “Salt-and-pepper” chromatin

• Background amyloid

• Common cell types

– Plasmacytoid

– Spindled

– Polygonal

 

For all types of MTC, the average 5-year survival rate is 78–92%

and the 10-year survival rate is 61–75%. Overall, the most important

prognostic factor for MTC is disease stage at presentation,

and the primary treatment modality for MTC is surgery. Because

the treatment of MTC involves complex decision making and

surgical intervention (e.g., total thyroidectomy with or without

neck dissection), an accurate FNA diagnosis is essential to avoid

multiple unnecessary surgeries.

MTC frequently metastasizes at an early stage to regional lymph

nodes in the central and lateral neck as well as to the superior

mediastinum. For this reason, some form of lymph node dissection

is usually performed in addition to total thyroidectomy. At some

institutions, patients receive a central neck and upper mediastinal

lymph node dissection, and for patients with palpable nodal disease,

either ipsilateral or bilateral modified radical neck dissection

(MRND) is performed. Postoperatively, calcitonin and CEA serum

levels are routinely monitored to help identify those patients with

recurrent or metastatic disease.

References:

Douglas P.Clark, William C.Faquin. Thyroid Cytopathology (second edition). Essential in Cytopathology Series Editor Dorothy L.Rosenthal.  Springer, 151-166

 

 

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