Clinicians sometimes meet some patients whose clinical manifestations are beyond their own knowledge and cannot be classified according to existing knowledge. This case may be a rare case. Of course, to determine whether a case is rare, we need to search the literature database carefully and comprehensively to see if anyone else has reported it. Very few cases may be caused by special tissue diseases or physiological dysfunction. Therefore, whenever we encounter special and rare cases, we should try our best to use all kinds of modern means to carry out detection and research, and strive to further clarify the pathogenesis of the disease.

If two or more rare diseases coexist in the same patient, or a syndrome and a rare symptom coexist in the same patient, it may indicate that there is some correlation between them, and even one disease may be caused by another. Such case reports should have sufficient laboratory and imaging evidence or pathological evidence to support the mechanism and causality of comorbidity.

The abnormal clinical manifestations or prognosis of some cases may provide new clues for pathology, etiology or treatment mechanism, and provide basis for further prospective research. These abnormal manifestations or special outcomes of diseases can be caused by drugs or other intervention measures, or they can be unique manifestations of diseases. This kind of case report should have enough evidence of clinical examination and various examinations to prove the certainty of abnormal performance and special prognosis.