Use additional codes for functional activity.
Unlike many conditions that have greater granularity in ICD-10 than ICD-9, you can expect a direct crosswalk for malignant thyroid cancer.
Currently, you report the condition as 193 (Malignant neoplasm of thyroid gland). When ICD-10 goes into effect beginning Oct. 1, 2014, you’ll need to report the same condition using ICD-10 code C73 (Malignant neoplasm of thyroid gland).
Functional Activity is Different
Functional thyroid disorders range from the thyroid gland becoming overactive (hyperthyroidism, 242.xx in ICD-9) or underactive (hypothyroidism, 244.x in ICD-9).
In ICD-10-CM, disorders of the thyroid gland are classified to categories E00-E07. The categories are as follows:
ICD difference: The coding rules related to thyroid diseases will be essentially the same in ICD-10 as in ICD-9. However, ICD-10-CM will classify some conditions to different sections. For instance, The ICD-9 code for postsurgical hypothyroidism is 244.0, which is in the hypothyroidism category. In ICD- 10, on the other hand you will not locate postsurgical hypothyroidism under category E03. Instead, you will code it with E89.0, which is under category E89 (Postprocedural endocrine and metabolic complications and disorders, not elsewhere classified).