Thyroid & parathyroid

Congenital / metabolic anomalies

Solid cell nests / ultimobranchial body remnants



Last author update: 1 September 2015
Last staff update: 5 September 2023

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PubMed Search: Solid cell nests [title] thyroid

Andrey Bychkov, M.D., Ph.D.
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Cite this page: Bychkov A. Solid cell nests / ultimobranchial body remnants. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/thyroidsolidcellnests.html. Accessed March 19th, 2024.
Definition / general
Terminology
  • Also known as ultimobranchial body remnants, ultimobranchial body nests
  • Solid cell nests are the ultimobranchial body remnants in postnatal life
  • Rarely called compact cell nests, solid cell rests
Epidemiology
Sites
  • Located in the middle or occasionally in the upper third of the thyroid lateral lobes and placed in a central to paracentral and slightly dorsal longitudinal axis (J Pathol 1988;155:191)
Clinical features
Diagnosis
  • Usually an incidental microscopic finding
Case reports
Microscopic (histologic) description
  • Small cells in solid structures (50 - 1000 μm) interspersed between follicles
  • Usually surrounded by stroma and demarcated by adjacent thyroid follicles
  • Lobulated, nested or irregular shape on low power
  • Multiple foci (2 - 8 per section) are common (Histopathology 2016;68:866)
  • Composed of two cell populations - predominant main cells and a minority of C cells
    • Sometimes with intermingled cystic structures containing mucin and mixed follicles
  • Main cells:
    • Polygonal / elongated to round to spindle cells
    • Scant amphophilic or rarely deeply eosinophilic cytoplasm with squamoid features (but no intercellular bridges)
    • Nuclei are centrally located, oval to fusiform, with finely granular chromatin, uneven nuclear membrane, occasional nuclear grooves
  • C cells: minor population of cells with clear cytoplasm and centrally located, small compact nuclei
  • May contain ciliated columnar cells
  • May also contain cells with follicular lumen-like pattern (mixed follicles)
  • Usually have a tropism to lymphocytes because of the common embryologic derivation of SCNs and the thymus (Pathol Int 2006;56:150, Hum Pathol 2009;40:1029)
  • C cells in small clusters are common in the vicinity of solid cell nests
  • Cartilage and adipose tissue are rarely seen (Hum Pathol 1994;25:684)
  • Asioli et al classified SCN based on the solid (types 1 - 2) or cystic (types 3 - 4) patterns (Endocr Pathol 2009;20:197):
    • Type 1 (floret-like) is composed of main cells, characterized by round to oval or elongated cells with scant cytoplasm, centrally located oval to fusiform nuclei, and occasional nuclear grooves
      • The cells form round to oval groups, surrounded by lymphocytes
    • Type 2 SCN (epidermoid-like) are made of larger, polygonal cells with an epidermoid appearance
    • Type 3 has cystic architecture lined by flattened or polygonal cells
    • Type 4 SCNs (mixed follicles) have a follicular appearance and contain both follicular epithelium and small main cells
Microscopic (histologic) images

Contributed by Andrey Bychkov, M.D., Ph.D. and AFIP

Solid cell nests

Histologic mimics of SCN

Solid cell nests: p63

Solid cell nests: thyroglobulin-

Solid cell nests


Nested pattern

Cystic SCN

Clear cells

Occasional nuclear grooves

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Type 1 and 2 solid cell nests



Images hosted on other servers:
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Admixture of main and C cell

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High mag of solid cell nests

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Various stains

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Galectin 3, CEA

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Conventional solid cell nests

Cytology description
  • Cohesive cellular group consisting of polygonal squamoid cells with lightly eosinophilic cytoplasm (no intercellular bridges), elongated to columnar shaped cells with clear cytoplasm, and scattered lymphocytes
  • Nucleus is large and centrally located, slightly irregular with evenly distributed chromatin and chromocenter (Hum Pathol 2004;35:465)
Positive stains
Negative stains
Electron microscopy description
Molecular / cytogenetics description
Differential diagnosis
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