Medullary Thyroid Carcinoma: Definition, Morphologic features, Prognosis

00:05:26
https://www.youtube.com/watch?v=qhvLkPDjDyI

概要

TLDRThis video provides an overview of medullary thyroid carcinoma (MTC), a less common form of thyroid cancer that arises from parafollicular or C cells. MTC accounts for about 5% of thyroid cancers and has key distinguishing features: familial occurrence, calcitonin secretion, and the presence of amyloid in the tumor stroma. Genetic mutations in the RET proto-oncogene are often involved, particularly in familial cases. MTC can present as a solitary nodule or lymph node enlargement, with progression potentially leading to metastasis. Histologically, tumor cells display a neuroendocrine pattern and amyloid may be present. The prognosis varies, with familial cases generally having a better survival rate than sporadic cases.

収穫

  • 🔍 Medullary thyroid carcinoma arises from parafollicular C cells.
  • 👥 Accounts for about 5% of thyroid carcinomas, equally affecting men and women.
  • 🧬 Familial cases often involve RET proto-oncogene mutations.
  • 🩸 Key features: calcitonin secretion and amyloid deposits.
  • 🩺 Symptoms include solitary nodules and possible lymph node involvement.
  • 📈 Prognosis: 60-70% 10-year survival rate; better in familial cases.
  • 🔬 Histological characteristics include nests of tumor cells and amyloid stroma.
  • 👥 Sporadic cases occur in older age; familial in younger age groups.
  • 🦠 Metastases are mostly regional; distant organ metastases are rare.

タイムライン

  • 00:00:00 - 00:05:26

    Medullary thyroid carcinoma is a rare type of thyroid cancer, comprising about 5% of all thyroid carcinomas. It arises from parafollicular or C cells and is equally common in both sexes. Key features include its familial occurrence, calcitonin secretion, and amyloid stroma. Approximately 10% of cases have a genetic background linked to RET proto-oncogene mutations, showing familial patterns such as multiple endocrine neoplasia types 2A and 2B, which involve pheochromocytoma and parathyroid adenoma. Sporadic cases generally manifest in middle and older age, while familial cases present earlier and are often bilateral and multicentric. Tumors secrete calcitonin and other peptides, leading to various clinical syndromes. Most tumors present as solitary nodules, with distinct histological features, including organoid patterns and amyloid stroma. While metastases can occur, distant spread is infrequent, and prognosis tends to be better for familial cases. The overall 10-year survival rate stands at 60-70%.

マインドマップ

ビデオQ&A

  • What is medullary thyroid carcinoma?

    Medullary thyroid carcinoma is a rare type of thyroid cancer derived from parafollicular or C cells.

  • How common is medullary thyroid carcinoma?

    It comprises about 5% of all thyroid carcinomas and is equally common in men and women.

  • What are the key distinctive features of medullary carcinoma?

    1. Familial occurrence, 2. Secretion of calcitonin, 3. Presence of amyloid stroma.

  • What genetic mutations are associated with familial medullary carcinoma?

    Familial medullary carcinoma is associated with point mutations in the RET proto-oncogene.

  • What are the symptoms of medullary thyroid carcinoma?

    Symptoms may include the presence of a solitary thyroid nodule, possible lymph node enlargement, and syndromes caused by hormone secretion.

  • What is the prognosis for medullary thyroid carcinoma?

    The overall 10-year survival rate is 60-70%, with a better prognosis in familial cases.

  • How does the histology of medullary carcinoma appear?

    Histologically, the tumor shows well-defined nests of tumor cells, amyloid stroma, and varies in cell arrangement.

  • Are distant metastases common in medullary thyroid carcinoma?

    Distant organ metastases are infrequent; regional lymph node metastases may occur.

  • What is the relevance of calcitonin in medullary carcinoma?

    Tumor cells secrete calcitonin, which can lead to clinical syndromes such as Cushing's syndrome.

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  • 00:00:02
    today i will talk about medullary
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    thyroid carcinoma medullary carcinoma is
  • 00:00:08
    a less frequent type derived from
  • 00:00:10
    parafollicular or c cells present in the
  • 00:00:13
    thyroid and comprises about five percent
  • 00:00:16
    of thyroid carcinomas it is equally
  • 00:00:19
    common in men and women
  • 00:00:24
    there are three distinctive features
  • 00:00:25
    which distinguish medullary carcinoma
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    from the other thyroid carcinomas these
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    are
  • 00:00:32
    1. it's familial occurrence 2. secretion
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    of calcitonin and other peptides 3.
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    amyloid's
  • 00:00:42
    trauma 1. familial occurrence
  • 00:00:46
    most cases of medullary carcinoma occur
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    sporadically but about 10 percent have a
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    genetic background with point mutation
  • 00:00:54
    in ret proto-oncogene located on
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    chromosome 10q
  • 00:01:00
    the familial form of medullary carcinoma
  • 00:01:03
    has association with
  • 00:01:05
    viochromocytoma and parathyroid adenoma
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    multiple endocrine neoplasia mn2a or
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    with pheochromocytoma and multiple
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    mucosal neuromas men 2b
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    the sporadic cases occur in the middle
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    and
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    old age fifth sixth decades and are
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    generally unilateral
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    while the familial cases are found at
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    younger age second third decades and are
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    usually bilateral and multicentric
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    2. secretion of calcitonin and other
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    peptides
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    like normal c cells tumor cells of
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    metallary carcinoma secrete calcitonin
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    the hypocalcemic hormone
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    in addition the tumor may also elaborate
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    prostaglandins histamine ace
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    somatostatin vasoactive intestinal
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    peptide vip and act
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    these hormonal aberrations are
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    responsible for
  • 00:02:08
    a number of clinical syndromes such as
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    carcinoid syndrome cushing's syndrome
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    and diarrhea
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    three amyloid stroma
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    most medullary carcinomas have amyloid
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    deposits in the stroma which stains
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    positively with usual amyloid stains
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    such as congo red
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    the amyloid deposits are believed to
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    represent stored calcitonin derived from
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    neoplastic c cells in the form of pro
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    hormone
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    most cases of medullary carcinoma
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    present a solitary thyroid nodule but
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    sometimes an enlarged cervical lymph
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    node may be the first manifestation
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    morphologic features grossly the tumor
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    may either appear as a unilateral
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    solitary nodule sporadic form
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    or have bilateral and multicentric
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    involvement familial form
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    however sporadic neoplasms also
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    eventually spread to the contralateral
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    lobe
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    cut surface of tumor in both forms shows
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    well-defined tumor areas which are firm
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    to hard gray white to yellow brown with
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    areas of hemorrhages and necrosis
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    histologically the features are as under
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    1. tumor cells like other neuroendocrine
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    tumors for example carcinoid islet cell
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    tumor paragonglioma
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    medullary carcinoma of the thyroid 2 has
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    a well-defined organoid pattern forming
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    nests of tumor cells separated by
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    fibrovascular septa
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    sometimes the tumor cells may be
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    arranged in sheets
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    ribbon pseudo papillae or small
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    follicles
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    the tumor cells are uniform and have the
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    structural and functional
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    characteristics of c cells less often
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    the neoplastic cells are spindle shaped
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    2. amyloid stroma
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    the tumor cells are separated by amyloid
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    stroma derived from altered calcitonin
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    which can be demonstrated by immunostain
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    for calcitonin
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    the staining properties of amyloid are
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    similar to that seen in systemic
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    amyloidosis and may have areas of
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    irregular calcification but without
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    regular laminations seen in samoa bodies
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    3. c cell hyperplasia familial cases
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    generally have c cell hyperplasia as a
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    precursor lesion but not in sporadic
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    cases
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    most medullary carcinomas are slow
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    growing regional lymph node metastases
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    may occur but distant organ metastases
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    are infrequent
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    prognosis the prognosis is better in
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    familial form than in the sporadic form
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    overall 10-year survival rate is 60 to
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    70 percent
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    [Music]
  • 00:05:26
    you
タグ
  • medullary thyroid carcinoma
  • thyroid cancer
  • calcitonin
  • familial occurrence
  • RET proto-oncogene
  • amyloid stroma
  • neuroendocrine tumors
  • prognosis
  • cervical lymph nodes
  • hormonal syndromes