ICD Body System
Date amended:
External
Statements of Principles
Current RMA Instruments

Reasonable Hypothesis SOP

39 of 2022

Balance of Probabilities SOP

40 of 2022

Changes from previous Instruments

ICD Coding
  • ICD-9-CM Code: 193
  • ICD-10-AM Code: C73
Brief description

This SOP covers malignant neoplasms of the follicular cells of the thyroid gland.  Medullary carcinoma, arising in the parafollicular cells of the thyroid, is excluded.

Confirming the diagnosis

This diagnosis is based on histopathology of the thyroid gland, from a (fine-needle aspiration) biopsy or surgery.

The relevant medical specialist is a general surgeon or endocrinologist.

Additional diagnoses covered by SOP
  • anaplastic thyroid carcinoma
  • follicular thyroid carcinoma
  • Hurthle cell thyroid cancer
  • mixed medullary and follicular thyroid cancer
  • noninvasive follicular variant of papillary thyroid carcinoma (NI-FVPTC)
  • papillary thyroid carcinoma
  • thyroid neoplasms of uncertain malignant potential
Conditions excluded from SOP
  • Adenoma of thyroid#
  • Carcinoid of thyroid#
  • Hodgkin’s lymphoma of the thyroid*
  • Medullary carcinoma of the thyroid# – this is a neoplasm arising from the parafollicular cells (also called C-cells).
  • Non-Hodgkin lymphoma of the thyroid*
  • Secondary/metastatic cancer involving the thyroid (code to primary cancer site)
  • Soft tissue sarcoma of the thyroid*
  • Thyroid hyperplasia#

* another SOP applies

# non-SOP condition

Clinical onset

The condition usually presents with a thyroid nodule (lump) detected by the patient, by a doctor on clinical examination, or incidentally on imaging performed for another reason.

Clinical worsening

The only SOP worsening factor is for inability to obtain appropriate clinical management. Appropriate treatment typically comprises surgery, followed by radioiodine therapy (when indicated) and thyroid hormone suppression therapy.