Imaging Pearls ❯ Adrenal ❯ Adrenal Infection
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- Results Adrenal abscesses are very rare in practice with few cases documented in the literature. They most frequently occur due to disseminated infection, presenting with acute abdominal pain, weight loss, lightheadedness, and fever. Their presentation on imaging is characterized by a large, multiloculated lesion with peripheral enhancement. Treatment options include antimicrobial agents, surgical intervention, and percutaneous abscess drainage.
Conclusion Adrenal abscesses may closely mimic other malignant and benign adrenal and abdominal masses. Due to their extreme rarity, they are often not included in the differential diagnosis of large abdominal masses. However, these lesions should be considered in acute abdomen presentations, especially with history of infection, to facilitate accurate and timely diagnosis and management.
Adrenal abscesses: an uncommon and unexpected cause of the acute abdomen.
Smith CW, Arshad H, Fishman EK.
Emerg Radiol. 2026 Feb;33(1):119-127. - An adrenal abscess is an exceedingly rare, purulent lesion in the adrenal gland that can present as acute abdomen in the emergency department (ED). Though overwhelmingly caused by infectious causes, they can also result from gastrointestinal perforation, surgical complications, and trauma. Age seems to have little correlation to the prevalence of adrenal abscesses; however, males are typically more affected than females. Common clinical manifestations include acute abdominal pain, weight loss, fever, and hyperpigmentation. Adrenal abscesses frequently present on imaging with diffuse adrenal enlargement, heterogeneously enhancing lesions, and adrenal thickening with peripheral enhancement.
Adrenal abscesses: an uncommon and unexpected cause of the acute abdomen.
Smith CW, Arshad H, Fishman EK.
Emerg Radiol. 2026 Feb;33(1):119-127. - These lesions most frequently occur in the setting of bacteremia or other infectious agents. In a systematic review conducted by Gligorijevic et al., 86.4% of adrenal abscess cases revealed a causative pathogen through histopathological analysis . Fungal etiology was most common, of which Histoplasma capsulatum was the most prevalent. For those with bacterial etiologies, Mycobacterium tuberculosis was the most common pathogenic agent. Other cases have been documented where Nocardia cyriacigeorgica, Escherichia coli, and Peptostreptococcus are the causative pathogens. However, the scope of causative pathogens is broad and ill-defined; all pathogenic agents should be considered potential etiologies for an adrenal abscess.
Adrenal abscesses: an uncommon and unexpected cause of the acute abdomen.
Smith CW, Arshad H, Fishman EK.
Emerg Radiol. 2026 Feb;33(1):119-127. - Adrenal abscesses typically present on CT scans with diffuse adrenal enlargement, adrenal wall thickening, nodularity, and heterogeneous masses with peripheral enhancement. There is no literature reported on the typical attenuation ranges of adrenal abscesses. However, CT imaging from Case #1 and Case #2 demonstrated attenuation ranges of − 10–50 HU and − 30–80 HU, respectively. Post-processing reconstruction techniques are significantly improving and may help achieve greater imaging detail to assist with adrenal evaluation.
Adrenal abscesses: an uncommon and unexpected cause of the acute abdomen.
Smith CW, Arshad H, Fishman EK.
Emerg Radiol. 2026 Feb;33(1):119-127. - In conclusion, adrenal abscess is an often-overlooked etiology that can present with acute abdomen. Imaging is a crucial diagnostic modality for evaluating adrenal abscesses; however, pathological study is frequently required to accurately rule out malignancy due to overlapping imaging characteristics. This review highlights the critical role of imaging in diagnosing adrenal abscesses to guide accurate management planning. Despite their rarity in clinical scenarios, adrenal abscesses should be a thoroughly considered etiology for acute abdominal presentations. In patients presenting with acute abdomen and a multiloculated adrenal mass, adrenal abscess should be considered in the differential diagnosis. This consideration is especially important in patients with a history of infection or sepsis. Awareness of this possibility is a key underpinning of accurate diagnosis and treatment for adrenal lesions.
Adrenal abscesses: an uncommon and unexpected cause of the acute abdomen.
Smith CW, Arshad H, Fishman EK.
Emerg Radiol. 2026 Feb;33(1):119-127.
- Results Adrenal abscesses are very rare in practice with few cases documented in the literature. They most frequently occur due to disseminated infection, presenting with acute abdominal pain, weight loss, lightheadedness, and fever. Their presentation on imaging is characterized by a large, multiloculated lesion with peripheral enhancement. Treatment options include antimicrobial agents, surgical intervention, and percutaneous abscess drainage.
Conclusion Adrenal abscesses may closely mimic other malignant and benign adrenal and abdominal masses. Due to their extreme rarity, they are often not included in the differential diagnosis of large abdominal masses. However, these lesions should be considered in acute abdomen presentations, especially with history of infection, to facilitate accurate and timely diagnosis and management.
Adrenal abscesses: an uncommon and unexpected cause of the acute abdomen.
Smith CW, Arshad H, Fishman EK.
Emerg Radiol. 2025 Nov 21. doi: 10.1007/s10140-025-02417-3. in press - An adrenal abscess is an exceedingly rare, purulent lesion in the adrenal gland that can present as acute abdomen in the emergency department (ED). Though overwhelmingly caused by infectious causes, they can also result from gastrointestinal perforation, surgical complications, and trauma. Age seems to have little correlation to the prevalence of adrenal abscesses; however, males are typically more affected than females. Common clinical manifestations include acute abdominal pain, weight loss, fever, and hyperpigmentation. Adrenal abscesses frequently present on imaging with diffuse adrenal enlargement, heterogeneously enhancing lesions, and adrenal thickening with peripheral enhancement.
Adrenal abscesses: an uncommon and unexpected cause of the acute abdomen.
Smith CW, Arshad H, Fishman EK.
Emerg Radiol. 2025 Nov 21. doi: 10.1007/s10140-025-02417-3. in press - The main diagnostic challenge of adrenal abscesses is its close resemblance to other benign and malignant adrenal lesions. It is crucial to sufficiently rule out malignancy in the differential diagnosis to guide appropriate management. ACC often presents on CT as a large (>4 cm), heterogeneously enhancing mass with invasion into adjacent structures and absolute washout < 60%. Approximately 40–60% of ACCs are functional producing steroids or androgens that could be contrasted from abscesses which are non-functional. ACC often undergoes necrotic or hemorrhagic changes presenting with a central non-enhancing region and thin enhancing capsule on CT . On the other hand, abscesses are also heterogenous but often multiloculated with thick enhancing capsule and may have gas bubbles due to bacterial activity.
Adrenal abscesses: an uncommon and unexpected cause of the acute abdomen.
Smith CW, Arshad H, Fishman EK.
Emerg Radiol. 2025 Nov 21. doi: 10.1007/s10140-025-02417-3. in press - They also resemble benign adrenal cysts and adrenal hemorrhages. Pseudocysts, the most common type of adrenal cyst, can result from prior hemorrhage, infection or within an underlying tumor. Their appearance can range from cystic, mixed to completely solid masses. Endothelial and epithelial cysts are generally round, well-defined, and homogenous in nature with a low attenuation [18]. However, the heterogenous enhancement with peripheral rim and gas bubbles are key differentiating features for abscesses. Cysts are often slow-growing with a reported mean growth rate of 1.1 ± 5.4 cm per year. Abscesses tend to grow rapidly as seen in Case #1, where the mass grew from 7.1 × 4.5 × 5.8 cm to 9.1 × 5.3 × 8.5 cm in ten days.
Adrenal abscesses: an uncommon and unexpected cause of the acute abdomen.
Smith CW, Arshad H, Fishman EK.
Emerg Radiol. 2025 Nov 21. doi: 10.1007/s10140-025-02417-3. in press - There are limitations to this review. Due to the rarity of adrenal abscesses, there is a paucity of literature, with most limited to case reports. The scarcity of literature on this topic may introduce selection bias, as published cases are likely to represent more severe or diagnostically clear examples. Milder or indeterminate cases may be underreported. Additionally, our review is retrospective in nature. The two reported cases from our institution also lack follow-up data, and clinical outcomes were not documented.
Adrenal abscesses: an uncommon and unexpected cause of the acute abdomen.
Smith CW, Arshad H, Fishman EK.
Emerg Radiol. 2025 Nov 21. doi: 10.1007/s10140-025-02417-3. in press - In conclusion, adrenal abscess is an often-overlooked etiology that can present with acute abdomen. Imaging is a crucial diagnostic modality for evaluating adrenal abscesses; however, pathological study is frequently required to accurately rule out malignancy due to overlapping imaging characteristics. This review highlights the critical role of imaging in diagnosing adrenal abscesses to guide accurate management planning. Despite their rarity in clinical scenarios, adrenal abscesses should be a thoroughly considered etiology for acute abdominal presentations. In patients presenting with acute abdomen and a multiloculated adrenal mass, adrenal abscess should be considered in the differential diagnosis. This consideration is especially important in patients with a history of infection or sepsis. Awareness of this possibility is a key underpinning of accurate diagnosis and treatment for adrenal lesions.
Adrenal abscesses: an uncommon and unexpected cause of the acute abdomen.
Smith CW, Arshad H, Fishman EK.
Emerg Radiol. 2025 Nov 21. doi: 10.1007/s10140-025-02417-3. in press - The normal adrenal gland can show physiological FDG uptake, which is usually mild with average maximum standardized uptake values (SUVmax) between 0.83 and 0.95. Infections such as CMV, tuberculosis, histoplasmosis, or fungal infection often exhibit increased FDG uptake, characterized by SUVmax values surpassing 2.5. Abnormal uptake may be diffuse or peripheral with central photopenia representing necrotic changes.However, such uptake patterns lack specificity, as both benign conditions (eg, adrenal hyperplasia, and adenomas) and malignant tumours (eg, lymphoma, pheochromocytoma, adrenocortical carcinoma, and metastasis) may also display increased FDG uptake, with variable SUVmax values. Notably, when using an SUVmax threshold of 3.1, FDG PET/CT has demonstrated sensitivity and specificity of 98.5% and 92%, respectively, in discriminating between benign and malignant adrenal lesions.
Adrenal infections update: how radiologists can contribute to patient care
Jorge Abreu-Gomez , Vanessa Murad Shereen Ezzat et al.
Br J Radiol 2025 Feb 11;98(1168):496–508 - On CT, adrenal inflammation (adrenalitis) is characterized by either unilateral or bilateral adrenal enlargement with effacement of the adrenal borders and adjacent fat stranding. In addition, adrenal haemorrhage typically presents as a round or oval lesion with varying degrees of attenuation depending on the stage of haemorrhage. In the acute bleeding phase, the lesion is predominantly homogeneously hyperdense, whereas it becomes more heterogeneous during the subacute stage. This can be associated with haziness along its margins and fat stranding.
Adrenal infections update: how radiologists can contribute to patient care
Jorge Abreu-Gomez , Vanessa Murad Shereen Ezzat et al.
Br J Radiol 2025 Feb 11;98(1168):496–508 - Bacteria contribute to adrenal damage through direct colonization of adrenal tissue and through the disruption of biochemical and endocrinological host responses due to the release of endotoxins, exotoxins, and the activation of proinflammatory cytokines. In the acute stages, there is often an upregulation of the hypothalamic-pituitary-adrenal (HPA) axis, resulting in an increase in adrenocorticotrophic hormone (ACTH). This hormonal imbalance sets the stage for adrenal haemorrhage predisposition. Bacterial sepsis and pyogenic infections pose a particular risk for bilateral adrenal haemorrhage, potentially leading to adrenal insufficiency, known as Waterhouse-Friderichsen Syndrome. Several bacteria have been associated with this syndrome, including group A streptococcal infections, Neisseria meningitidis, Haemophilus Influenza, and pneumococcus, among others.
Adrenal infections update: how radiologists can contribute to patient care
Jorge Abreu-Gomez , Vanessa Murad Shereen Ezzat et al.
Br J Radiol 2025 Feb 11;98(1168):496–508 - Imaging manifestations of tuberculous involvement of the adrenal glands varies based on the severity and duration of infection. In the setting of active tuberculosis, particularly in pulmonary cases, the adrenals often display thickening and increased size, usually in a bilateral fashion. This phenomenon is attributed to two distinct pathophysiological mechanisms. The first involves the primary infection of the adrenal parenchyma by the bacillus, while the second results from the activation of the hypothalamus-pituitary-adrenal axis in response to stress induced by Mycobacterium.Bilateral enlargement of the glands associated with preserved shape suggests the latter. Conversely, atrophic and calcified glands are indicative of remote or inactive infection.
Adrenal infections update: how radiologists can contribute to patient care
Jorge Abreu-Gomez , Vanessa Murad Shereen Ezzat et al.
Br J Radiol 2025 Feb 11;98(1168):496–508 - CT imaging plays a pivotal role in identifying infective sources in the abdomen, with radiologists needing to recognize specific features that suggest adrenal involvement. Although imaging features are often non-specific, radiologists can crucially guide clinical colleagues towards a potential diagnosis. For example, the appearance of thickening in single or bilateral adrenal glands, combined with ill-defined margins and surrounding fat stranding in a critically ill or septic patient, should raise the suspicion of an infective agent. Such presentations are unusual for adrenal hyperplasia, which typically does not show surrounding stranding, and differ from malignancy, which often exhibits nodular or irregular adrenal parenchyma replacement. Additional signs like rim-enhancing collections or abscesses within the adrenal or in distant organs provide further evidence of infection. In cases of bilateral involvement, specific agents such as histoplasmosis and tuberculosis should be considered.
Adrenal infections update: how radiologists can contribute to patient care
Jorge Abreu-Gomez , Vanessa Murad Shereen Ezzat et al.
Br J Radiol 2025 Feb 11;98(1168):496–508 - Key CT Findings of Adrenalitis
Size and Shape: Enlarged adrenal glands, often retaining their original shape (adreniform) or appearing as a mass-like lesion.
Enhancement Pattern:
Subacute/Active: Peripheral enhancement with central hypodense necrosis.
Early Infection: Heterogeneous or homogeneous enhancement.
Density: Areas of low attenuation (necrosis).
Adjacent Tissue: Surrounding fat stranding, indicating inflammation.
Chronic Phase: Glands may become small, atrophic, and develop calcifications.
- The most common laboratory findings were low cortisol (51.9%), elevated ACTH (43.2%), hyponatremia (88.2%) and anemia (83.3%). Adrenal cultures were positive in 86.4% cases, with Histoplasma capsulatum (37.3%) being the leading causative agent. Blood cultures were positive in 30% of patients. The majority of the adrenal infections occurred through secondary dissemination from other infectious foci and abscesses were more commonly bilateral (70%). A total of 46.4% of patients developed long-term adrenal insufficiency requiring treatment. Abscess drainage was performed in 7 patients (8.3%) and adrenalectomy was performed in 18 (21.4%) patients. The survival rate was 92.9%.
Adrenal Abscesses: A Systematic Review of the Literature.
Gligorijevic N, et al.
J Clin Med. 2023 Jul 11;12(14):4601. - Our review shows that adrenal abscesses are usually caused by fungal pathogens, and among these, Histoplasma capsulatum is the most common. The adrenal glands are usually involved in a bilateral fashion and become infected through dissemination from other primary sources of infection. Long-term adrenal insufficiency develops in 46% of patients, which is more common than what is observed in non-infectious etiology of adrenal gland disorders. Mortality is about 7%, and the presence of thrombocytopenia is associated with worse prognosis.
Adrenal Abscesses: A Systematic Review of the Literature.
Gligorijevic N, et al.
J Clin Med. 2023 Jul 11;12(14):4601. - The most common CT findings were bilateral diffuse adrenal enlargement, heterogeneously enhancing adrenal lesions, nodular changes and diffuse adrenal thickening with peripheral enhancement. An advantage of using the CT scan in the cases of suspected adrenal involvement was detecting potential intrabdominal and intrathoracic infection dissemination without the need to utilize additional imaging studies.
Adrenal Abscesses: A Systematic Review of the Literature.
Gligorijevic N, et al.
J Clin Med. 2023 Jul 11;12(14):4601.
- “Peripheral lobar calcifications represent another pattern that delineates end-stage kidney disease and are characteristic of TB. With this pattern, lobar calcific rims usually outline the periphery of distorted renal lobes as a sequela of papillary necrosis. A focal globular pattern of calcifi-cation of the entire renal lobe, when seen, is often a sequela of a granulomatous mass. Lobar calcification, in which a densely calcified rim out-lines the periphery of the distorted renal lobes, is considered to be characteristic of renal TB.”
Imaging Manifestations of Genitourinary Tuberculosis
Muhammad Naeem et al.
RadioGraphics 2021;41:1123–1143 - “Renal TB has a propensity to extend into the psoas sheath, perirenal and pararenal spaces (resulting in cold abscesses), sinus tracts, and fistulas and can also be seen in conjunction with tuberculous spondylitis (Pott disease). Extension to other viscera in the abdo-men also has been described, with kidney-to–ali-mentary tract fistulas being the most common. Other fistulous communications to the skin, solid viscera, and bronchi also may be seen .”
Imaging Manifestations of Genitourinary Tuberculosis
Muhammad Naeem et al.
RadioGraphics 2021;41:1123–1143 - “TB commonly has long-segment involvement of the ureter, often with periureteric fat strand-ing during the early phase of infection. Transitional cell cancer usually manifests as focal, often asymmetric wall thickening of the ureter without fat stranding. Calcifications can manifest with TB and need to be differentiated from schistosomiasis. With TB, the calcifications are contiguous with the renal collecting system, whereas with schistosomiasis, they are more focal and more common in the urinary bladder. Also, ureteral calcifications in TB are intraluminal and appear as a cast of the ureter, whereas with schistosomiasis, calcifications are intramural.”
Imaging Manifestations of Genitourinary Tuberculosis
Muhammad Naeem et al.
RadioGraphics 2021;41:1123–1143
- "Adrenal infections are rare but important causes of adrenal insufficiency. These infections are the leading cause of adrenal insufficiency in the developing world, where they are more prevalent. They are more common in immunocompromised subjects, and infections may be primary or secondary to systemic infections. Mycobacterium tuberculosis accounts for 30% of the reported cases. Histoplasma capsulatum, Nocardia asteroides, Aspergillus species, Cryptococcus neoformans, Pneumocystis jirovecii, and cytomegalovirus are among the other causes of adrenal infection.”
Cross‐sectional imaging features of unusual adrenal lesions: a radiopathological correlation
Karaosmanoglu AD et al.
Abdominal Radiology (2021) 46:3974–3994
- "Hematogenous spread of the Mycobacterium tuberculosis is the most common route for adrenal tuberculosis. The disease’s course may be highly insidious, and it may take years for the symptoms to become apparent and asymptomatic disease is also not uncommon. In patients with active tuberculosis, around 9% have signs of involvement in autopsy studies, and for the adrenal insufficiency to develop, approxi- mately more than 90% of the gland must be destroyed.”
Cross‐sectional imaging features of unusual adrenal lesions: a radiopathological correlation
Ali Devrim Karaosmanoglu et al.
Abdominal Radiology (2021) 46:3974–3994
- “Adrenal infections, although rare are important causes of adrenal insufficiency. Infection is the leading cause of adrenal insufficiency (Addison’s disease) in the developing world, with the most common agent Mycobacterium tuberculosis accounting for approximately 30% of reported cases. As with infections elsewhere in the body, adrenal infections are more common in the immunocompromised patient . Adrenal infections can be primary or secondary to systemic dissemination and adrenal involvement in systemic infection is reported in up to 80 percent of cases evaluated with autopsy.”
CT and MR imaging of acute adrenal disorders
Amar Udare et al.
Abdominal Radiology (2021) 46:290–302 - “Early tuberculous adrenalitis is seen as bilateral adrenal enlargement with central non-enhancing areas due to necrosis with peripheral enhancement. The imaging appearance of Histoplasmosis is indistinguishable from that of Tuberculosis and should be considered in the differential diagnosis in endemic areas, as adrenal insufficiency is seen in up to 50% of patients with disseminated histoplasmosis and is fatal if untreated. In chronic stages both tuberculosis and histoplasmosis are seen as atrophic adrenal glands with foci of calcification.”
CT and MR imaging of acute adrenal disorders
Amar Udare et al.
Abdominal Radiology (2021) 46:290–302
- "Adrenal infections, although rare are important causes of adrenal insufficiency. Infection is the leading cause of adrenal insufficiency (Addison’s disease) in the developing world, with the most common agent Mycobacterium tuberculosis accounting for approximately 30% of reported cases . As with infections elsewhere in the body, adrenal infections are more common in the immunocompromised patient. Adrenal infections can be primary or secondary to systemic dissemination and adrenal involvement in systemic infection is reported in up to 80 percent of cases evaluated with autopsy.”
CT and MR imaging of acute adrenal disorders
Amar Udare et al.
Abdominal Radiology https://doi.org/10.1007/s00261-020-02580-w - "Early tuberculous adrenalitis is seen as bilateral adrenal enlargement with central non-enhancing areas due to necrosis with peripheral enhancement. The imaging appearance of Histoplasmosis is indistinguishable from that of Tuberculosis and should be considered in the differential diagnosis in endemic areas, as adrenal insufficiency is seen in up to 50% of patients with disseminated histoplasmosis and is fatal if untreated. In chronic stages both tuberculosis and histoplasmosis are seen as atrophic adrenal glands with foci of calcification.”
CT and MR imaging of acute adrenal disorders
Amar Udare et al.
Abdominal Radiology https://doi.org/10.1007/s00261-020-02580-w