ICD-10 Code D39.12 – Neoplasm of uncertain behavior of left ovary (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D39.12 – Neoplasm of uncertain behavior of left ovary
What it is
D39.12 identifies a growth in the left ovary whose behavior cannot be determined as clearly benign or malignant. Use it when the record documents uncertain biologic behavior of that specific ovarian mass.
Clinical signs
Findings may include an adnexal or pelvic mass, pain, bloating, or an incidental imaging abnormality. Clinical features vary; refer to documentation, pathology, and imaging reports for the exact diagnosis.
When to use this code
Use D39.12 when the provider documents a neoplasm of uncertain behavior in the left ovary and does not classify it as benign or malignant. It is also appropriate when pathology or operative notes state uncertain behavior for that side. If the record only says “ovarian mass,” check documentation before coding.
Do not use for
Do not use this code for clearly benign ovarian cysts or documented ovarian cancer. If the mass is on the right ovary or both ovaries, choose the correct laterality code instead.
Coding tip
Confirm laterality and the wording “uncertain behavior” in the provider’s final diagnosis before assigning D39.12.