Diagnostic ultrasound ( PDFDrive )

CHAPTER 11 The Adrenal Glands 423
A
B
C
FIG. 11.8 Simple Adrenal Cysts in Two
Patients. (A) Sagittal sonogram demonstrates an
anechoic thin-walled cyst (arrow). (B) Sagittal and
(C) transverse images show a large simple cyst with
through transmission and a thin wall.
Infectious and Inlammatory Masses
Tuberculosis, histoplasmosis, blastomycosis, paracoccidiomycosis,
meningococcal, echinococcal, cytomegalovirus (CMV), herpesvirus,
and Pneumocystis infections are the most common infectious
diseases of the adrenal gland. 27,41,42
Tuberculosis of the adrenal gland has been noted to be one
of the most common causes of adrenal insuiciency worldwide. 43
Chest radiographs and sputum cultures may be negative even
in cases of positive adrenal tuberculous infection. Tuberculosis
and histoplasmosis are the two most common causes of adrenal
calciication in the adult population. 44 In the setting of disseminated
fungal infection, histoplasmosis and paracoccidiomycosis
are most commonly seen, where up to 80% have adrenal involvement
based on autopsy series. 45-47
Echinococcal infection of the adrenal gland rarely occurs in
isolation and is more oten seen in the presence of widespread
multiorgan echinococcal infection. 47,48
Immunosuppression resulting from acquired immunodeiciency
syndrome (AIDS), transplantation, or other causes
increases these patients’ risk for infectious involvement of the
adrenal gland. Common organisms include fungi (histoplasmosis),
mycobacteria, CMV, herpesvirus, Pneumocystis carinii (jiroveci),
human immunodeiciency virus (HIV), and toxoplasmosis. 41
Grizzle 42 described focal or difuse damage of the glands by CMV
in 70% of AIDS patients who died. In a study involving 74 AIDS
patients, Pulakhandam et al. found that up to 50% had CMV
infection at autopsy, of which 84% had adrenal involvement. 49
Bacterial adrenal abscesses are found more frequently in
neonates and are relatively uncommon in adults. 50,51 In the
neonate, hematogenous seeding of normal glands or those afected
by hemorrhage can result in abscess formation. 52
Sonographic Features
Sonographic features are indistinguishable among these infections,
and diagnosis is based on the patient’s geographic proile,
occupational exposure, and laboratory testing. Acute adrenal
involvement in granulomatous infections can lead to enlargement
of the gland, with nodular contours and hypervascularity.
Superimposed areas of necrosis and hemorrhage can also be
seen in cases of caseous necrosis. In the chronic setting, gland
atrophy and calciications can be present, which appear as
coarse echogenic foci with acoustic shadowing. 19,20 (Fig. 11.10,
Video 11.4).