The quadriceps are relatively spared, and remain strong until the late stages of disease, which is the reason IBM2 is often referred to as Quadriceps Sparing Myopathy (QSM). Signs and symptoms
Some early signs of HIBMs includes:

Difficulty walking on heels, and difficulty running;
Weak index finger;
Frequent loss of balance. On muscle biopsy, the typical finding includes inclusion bodies, rimmed vacuoles and accumulation of aberrant proteins similar to those found in senile plaques of Alzheimers disease (amyloid beta, hyperphosphorylated tau, amongst others)

Genetics
The different forms have different mutations and inheritance patterns. See the detailed descriptions for details

Mechanisms
The exact mechanisms of these diseases are not well understood. GNE/MNK a key enzyme in the sialic acid biosynthetic pathway, and loss-of-function mutations in GNE/MNK may lead to a lack of sialic acid, which in turn could affect sialoglycoproteins. GNE knockout mice show problems similar to people with IBM and in people with IBM dystroglycan has been found to lack sialic acid. However, the part of the dystroglycan that is important in muscle function does not seem to be affected. Another protein, neural cell adhesion molecule is under-sialyated in people with IBM, but as of 2016 it had no known role in muscle function. Diagnosis
The most useful information for accurate diagnosis is the symptoms and weakness pattern. If the quadriceps are spared but the hamstrings and iliopsoas are severely affected in a person between ages of 20 - 40, it is very likely HIBM will be at the top of the differential diagnosis.
Sperm granulomas form in 20-50% of vasectomy procedures. An injury to the epididymal epithelium is caused by penetration of germ cells into the epididymal supportive tissue. This infiltration of germ cells allows for the pathogenesis of sperm granulomas. Moreover, the penetration of germ cells leads to inflammatory and autoimmune reactions that further increase the risk of sperm granuloma formation.Sperm granuloma can also mimic the presence of an abnormal number of testis on ultrasound.Sperm granulomas are mostly asymptomatic. However, they can cause pain and swelling of the epididymis, spermatic cord, and testis. The pain usually radiates to the groin, the junctional area between the abdominal wall and the thigh, and can imitate the feeling of kidney spasms. Development of a Sperm Granuloma
Sperm granuloma is a common complication of vasectomy. Vasectomies are a common, effective procedure for sterilization of individuals assigned male at birth. History of trauma or epididymitis can also lead to sperm granuloma. In vasectomies, the vas deferens are cut and the two ends are tied to prevent sperm from passing. Sperm granuloma may then grow at the point where the vas deferens were cut. This could happen two to three weeks post procedure. Sperm granuloma can also form from sperm leaking from the vas deferens into the surrounding interstitium. Leakage of sperm elicits an immune response which can lead to chronic inflammation. A histological examination can confirm a sperm granuloma by checking for inflammatory markers such as macrophages and lymphocytes surrounding the sperm core. Treatment and prevention
Most sperm granulomas are asymptomatic and absorbed over time.