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Difficulty: MediumPathology and Biopsy Interpretation

A hospital pathology department is reviewing quality assurance protocols for evaluating thyroid nodules. Correct histopathologic identification is critical for determining whether a patient requires lobectomy, total thyroidectomy, or systemic therapy. Match each specific thyroid malignancy diagnosis with its pathognomonic microscopic description.

  • Papillary thyroid carcinomaBranching structures with fibrovascular cores, cells featuring optically clear nuclei, nuclear grooves, and calcified spherules
  • Medullary thyroid carcinomaNests of polygonal or spindle-shaped cells embedded in an amyloid-rich stroma derived from parafollicular C cells
  • Follicular thyroid carcinomaUniform cuboidal cells forming small follicles with clear evidence of capsular or vascular invasion
  • Anaplastic thyroid carcinomaUndifferentiated, highly pleomorphic spindle and giant cells with extensive necrosis and high mitotic index

Answer

Papillary carcinoma matches with optically clear nuclei and calcified spherules; Medullary carcinoma matches with amyloid-rich stroma; Follicular carcinoma matches with capsular or vascular invasion; and Anaplastic carcinoma matches with undifferentiated, highly pleomorphic cells.
Correct matching pairs accurately link each primary thyroid malignancy to its defining microscopic features. Papillary carcinoma is distinguished by its unique nuclear atypia and psammoma bodies. Medullary carcinoma is a neuroendocrine tumor of parafollicular C cells characterized by amyloid deposition. Follicular carcinoma requires the demonstration of architectural invasion (capsular or vascular) for diagnosis. Anaplastic carcinoma is an undifferentiated tumor marked by severe cellular atypia, high mitotic rates, and necrosis.

Step-by-Step Solution

1
Analyze the description of branching structures with optically clear nuclei and calcified spherules.
Identify these features as Orphan Annie eyes and psammoma bodies, which are pathognomonic for papillary thyroid carcinoma.
These nuclear and architectural features define the most common type of thyroid cancer, which frequently spreads via lymphatics.
2
Analyze the description involving an amyloid-rich stroma and parafollicular C cells.
Identify this as medullary thyroid carcinoma.
C cells produce calcitonin, which deposits as amyloid in the surrounding extracellular space; this tumor may be sporadic or associated with MEN 2 syndromes.
3
Analyze the description highlighting uniform cells forming follicles with capsular or vascular invasion.
Identify this as follicular thyroid carcinoma.
Unlike papillary carcinoma, follicular carcinoma cannot be diagnosed by fine-needle aspiration cytology alone; it requires evaluation of tissue architecture showing invasion to distinguish it from a benign adenoma.
4
Analyze the description of undifferentiated, highly pleomorphic spindle and giant cells with necrosis.
Identify this as anaplastic thyroid carcinoma.
These features characterize a highly aggressive, rapidly enlarging, undifferentiated tumor typically seen in older patients.

Key Concept

Histopathologic differentiation of thyroid malignancies
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Topics

Pathology and Biopsy Interpretation

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