Dye injected into the cyst rarely enters the joint, however, which has been attributed to the apparent formation of an effective and one-way "check valve", allowing fluid out of the joint, but not back in.In synovials, post-traumatic degeneration of connective tissue and inflammation have been considered as causes. Other possible mechanisms for the development of ganglion cysts include repeated mechanical stress, facet arthrosis, myxoid degeneration of periarticular fibrous tissues and liquefaction with chronic damage, increased production of hyaluronic acid by fibroblasts, and a proliferation of mesenchymal cells. Diagnosis
Ganglion cysts are diagnosed easily, as they are visible and pliable to touch. Radiographs in anteroposterior and lateral views should be obtained to exclude any more serious underlying pathology. Ultrasonography (US) may be used to increase diagnostic confidence in clinically suspected lesions or to depict occult cysts, because intratendinous ganglia are readily distinguished from extratendinous ganglia during dynamic ultrasonography, as microscopically, ganglionic cysts are thin-walled cysts containing clear, mucinous fluid. Treatment
If persons are not in pain, they should simply be reassured that the lump is not cancerous, and wait for the lump to disappear on its own. At least 33% resolve without treatment within six years, and 50% within 10 years.Surgical treatments remain the primary elective option for treatment of ganglion cysts. The progression of ganglion surgery worldwide is to use an arthroscopic or miniopening method.
Mycobacterium avium complex is a group of mycobacteria comprising Mycobacterium intracellulare and Mycobacterium avium that are commonly grouped because they infect humans together; this group, in turn, is part of the group of nontuberculous mycobacteria. These bacteria cause Mycobacterium avium-intracellulare infections or Mycobacterium avium complex infections in humans. These bacteria are common and are found in fresh and salt water, in household dust and in soil. MAC bacteria usually cause infection in those who are immunocompromised or those with severe lung disease. Description
In the Runyon classification, both bacteria are nonchromogens. They can be differentiated from M. tuberculosis and each other by commercially available DNA probes. : 245 They are characterized as Gram-positive, nonmotile, acid-fast, short to long rods. Colony characteristics

Usually, colonies are smooth, rarely rough, and not pigmented colonies. Older colonies may become yellow.Physiology

Growth on Löwenstein-Jensen medium and Middlebrook 7H10 agar occurs at 37°C after seven or more days. The complex can be (but is not often) resistant to isoniazid, ethambutol, rifampin, and streptomycin.Differential characteristics

M. intracellulare and M. avium form the M. avium complex (MAC). Remarkable ITS heterogeneity is seen within different M. intracellulare isolates. Type strains
M. intracellulare type strains include ATCC 13950, CCUG 28005, CIP 104243, DSM 43223, JCM 6384, and NCTC 13025.M. avium type strains include ATCC 25291, DSM 44156, and TMC 724. Human health
MAC bacteria enter most peoples body when inhaled into the lungs or swallowed, but only cause infection in those who are immunocompromised or who have severe lung disease such as those with cystic fibrosis or chronic obstructive lung disease (COPD).