Histopathologic and clinical features of medullary microcarcinoma and C-cell hyperplasia in prophylactic thyroidectomies for medullary carcinoma: a study of 42 cases.

Abstract

CONTEXT:

Prophylactic thyroidectomies are increasingly performed on patients at risk for developing medullary thyroid carcinoma (MTC); consequently, pathologists are more commonly encountering these specimens in routine practice.

OBJECTIVE:

To describe the detailed clinicopathologic features of prophylactic thyroidectomies for medullary carcinoma.

DESIGN:

We present a retrospective series of 42 prophylactic thyroidectomies for MTC performed for one or more of the following: family history of multiple endocrine neoplasia (MEN) or MTC, elevated serum calcitonin level, or detection of a RET proto-oncogene mutation.

RESULTS:

Patients included 22 men and 20 women (mean age, 26.2 years). Among those with known RET proto-oncogene mutations, affected sites included exons 10, 11, 14, and 16. In 93% (n = 39) of cases, either C-cell hyperplasia (n = 36), medullary microcarcinoma (MMC; n = 29), or medullary macrocarcinoma (n = 1) was found. C-cell hyperplasia was often multifocal (n = 30) and bilateral (n = 23) and included both nonnodular and nodular patterns. A total of 94% of C-cell hyperplasia cases and all MMC cases were microscopically detectable using hematoxylin-eosin stains. The MMCs were characterized by a complex microarchitectural pattern with a desmoplastic stromal response (n = 29) and focal amyloid deposition (n = 12). Most MMCs exhibited a solid pattern (n = 24) of round, polygonal, spindled, or plasmacytoid-shaped cells. Only 1 case of MMC showed evidence of metastatic disease to a pretracheal lymph node.

CONCLUSIONS:

Based upon our clinicopathologic findings and review of the literature, we conclude that thyroidectomies in at-risk patients are very frequently associated with C-cell hyperplasia and/or MMC; however, the clinical prognosis for these patients is very good.

• Authors: Demet Etit, William C Faquin, Randall Gaz, Gregory Randolph, Ronald A DeLellis, Ben Z Pilch
• Journal: Archives of pathology & laboratory medicine (Arch Pathol Lab Med) Vol. 132 Issue 11 Pg. 1767-73 (Nov 2008) ISSN: 1543-2165 [Electronic] United States
• PMID: 18976013 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• MAS1 protein, human
• Proto-Oncogene Mas
• Calcitonin
• Proto-Oncogene Proteins c-ret

Topics

• Adolescent
• Adult
• Aged
• Calcitonin (blood)
• Carcinoma, Medullary (pathology, prevention & control, surgery)
• Child
• Child, Preschool
• Female
• Humans
• Hyperplasia (pathology)
• Lymph Nodes (pathology)
• Male
• Middle Aged
• Mutation (genetics)
• Parathyroid Glands (pathology)
• Proto-Oncogene Mas
• Proto-Oncogene Proteins c-ret (genetics)
• Retrospective Studies
• Thyroid Gland (pathology, surgery)
• Thyroid Neoplasms (pathology, prevention & control, surgery)
• Thyroidectomy