We experienced challenges in establishing our patient’s accurate diagnosis; although initially SSc was a facile diagnosis, when the patient later developed muscle involvement, asthenia, muscle atrophy, muscle cytolysis, and cardiac involvement equivalent to myocarditis, with anti-SRP positivity, a series of theories appeared: to integrate cardiac and muscle involvement in the context of SSc, to reconsider the diagnosis as scleromyositis (a new diagnostic entity in rheumatology that is under-explored or neglected), or to conclude that we were faced with an overlapping syndrome of SSc and IMNM. Here, UCN2 is linked to Scleroderma Polymyositis Overlap Syndrome.