M61.161 Myositis ossificans progressiva, right lower leg

ICD-10-CM Diagnosis Code M61.161: Myositis ossificans progressiva, right lower leg

ICD-10-CM code M61.161 identifies myositis ossificans progressiva of the right lower leg. The condition is a rare autosomal dominant disease, also known as fibrodysplasia ossificans progressiva. This specific diagnosis code is billable and distinguishes the right lower leg from left or unspecified lower leg anatomical locations. 1 2 4 5

Plain-language overview

Myositis ossificans progressiva is a rare autosomal dominant disease with fewer than one thousand cases described, and it is also known as fibrodysplasia ossificans progressiva. 2

What this code represents

Code M61.161 represents the diagnosis myositis ossificans progressiva, right lower leg, and its semantic type is classified as a disease or syndrome within the ICD-10-CM terminology. 1

Coding details

The code M61.161 is a billable diagnosis code that specifies myositis ossificans progressiva of the right lower leg, distinguishing it from the left and unspecified lower leg codes. 5 4

Within the ICD-10-CM hierarchy, M61.161 has M61.16, myositis ossificans progressiva of the lower leg, as its parent concept, and the code record is currently active. 1

Documentation considerations

The terminology record for M61.161 specifies the right lower leg anatomical location, and code reference materials list distinct codes for left and unspecified lower leg presentations. 1 4

Coverage and utilization context

The code M61.161 appears in a Medicare billing and coding article concerning bisphosphonate drug therapy alongside codes for left and unspecified lower leg anatomical locations. 3

What the sources add

While terminology records define the code structure and laterality, clinical literature discusses available treatments for the condition, including oral ascorbic acid and intravenous bisphosphonates. 1 2

Multiple code reference sources consistently list M61.161 alongside M61.162 for the left lower leg and M61.169 for the unspecified lower leg to provide complete anatomical specificity. 3 4 5

Sources

1. ICD-10-CM M61.161 terminology record — National Cancer Institute Enterprise Vocabulary Services; accessed 2026-07-27.
2. MYOSITIS OSSIFICANS PROGRESSIVA: CASE REPORT — pmc.ncbi.nlm.nih.gov; accessed 2026-07-27.
3. Article - Billing and Coding: Bisphosphonate Drug Therapy (A56907) — cms.gov; accessed 2026-07-27.
4. M61.16 — medcode.ch; accessed 2026-07-27.
5. Codigo. The #1 Billing Agency for Medical Practices — codigo.care; accessed 2026-07-27.