Intraosseous migration of intratendinous calcification

Intraosseous migration of intratendinous calcification is a process in which calcific deposits penetrate and accumulate within the adjacent bone, creating a sclerotic lesion with bone edema^1,2.

This migration occurs during the resorptive stage of calcific tendinopathy natural evolution³.

In some cases, it can mimic a neoplastic or infectious lesion, and should not be overdiagnosed to avoid invasive diagnostic biopsies.

Epidemiology

This condition is a rare complication of calcific tendinitis and there is no reported incidence rate in the literature⁴.

Pathology

The mechanism by which calcifications erode the bone cortex and migrate into the bone is not fully understood. However, it is thought that enzymatic actions during the resorptive stage of calcific deposits may facilitate cortical osteolysis, allowing the calcifications to spread⁴.

Intraosseous migration can be divided into three types⁴:

• cortical erosion: This is the most common type of intraosseous migration. It occurs when the calcific deposits erode the cortex and allows the deposits to spread into the bone marrow.

• subcortical calcium migration: This type of migration occurs when the calcific deposits move from the bone cortex to the subcortical bone.

• intramedullary diffusion: occurs when the calcific deposits spread throughout the bone marrow.

Location

The reported locations are:

• posterior aspect of the humeral head ⁵ - the most common location

  • insertion of the rotator cuff tendons

• anteriomedial aspect of humerus / bicipital groove³

  • pectoralis major muscle insertion

• upper part of the linea aspera of the femur

  • gluteus maximus muscle insertion⁵

• lateral surface of the greater trochanter

  • insertion of gluteus medius muscle

Clinical presentation

It generally presents with acute pain, with no trauma history.

Radiographic features

Plain radiographs and CT

• amorphous soft tissue calcifications, usually the tendons

• cortical erosions adjacent to the tendon insertion - the first manifestation prior to migration

• amorphous subcortical calcification, osteolyis and sclerotic area - second phase of migration

• vanishing of a previous calcification

• follow up may demonstrate restitutio ad integrum, or persistence of a subcortical cyst in the previous location of the resorbed intraosseous calcification^2,3

MRI

• intratendinous T1 /T2 hypointensities corresponding to intratendinous calcifications

• non enhancing juxtacortical lesion of bone signal (T1 and T2 hypointense) adjacent to tendon insertion

• variable amount of bone marrow edema (T1 hypointense, T2 hyperintense)

• surrounding soft-tissue edema

• enhancement of adjacent tissues

• follow up may demonstrate restitutio ad integrum, or persistence of a subcortical cyst in the previous location of the resorbed intraosseous calcification^2,3

Treatement and prognosis

This is a self limiting condition and resolves completely with no specific treatement.

Differential diagnosis

Neoplastic

• osteoid osteoma

• chondroid lesions

• periosteal osteosarcoma

The acute symptoms, the absence of soft tisse mass and joint effusion generally rules out these differentials.

Infections

• osteomyelitis