Clinically Inapparent Bilateral Adrenal Masses Due to Histoplasmosis

Current perspective of adrenal histoplasmosis in India: A prospective study in a tertiary care hospital, Eastern India

PURPOSE

Adrenal histoplasmosis (AH) is an uncommon form of disseminated histoplasmosis caused by the dimorphic fungus Histoplasma capsulatum. Though, India is considered to be a non-endemic area for histoplasmosis, a high rise of AH cases is reported currently from various parts of India. Our study aimed to evaluate the current perspective of adrenal histoplasmosis in India by reviewing its clinical course, differential diagnosis, treatment, and mortality of our eleven confirmed cases of AH along with the review of authentic reported AH cases from India.

MATERIAL &METHOD

Clinical materials were taken from radiologically suspected all 15 cases either with unilateral or bilateral adrenal enlargement, referred between 2018 and 2020 for microbiological investigations. Fungal stain and fungal culture along with other tests for possible differential diagnosis with AH were conducted.

RESULT

Out of fifteen incidentaloma detected by radio-imaging, eleven cases of AH had been diagnosed in our hospital with yield of Rhodotorula spp. in one mimicking case. Nine of them were male (82%) and all were HIV nonreactive, which corroborates with the literature review. All of them had nonspecific clinical presentation of chronic abdominal pain, fever, weight loss, and anorexia. Four developed primary adrenal insufficiency, which are similar to the literature review (41%). On treatment with itraconazole and/or amphotericin B, all patients survived except one lost in follow-up.

CONCLUSION

Male preponderance and non-compromised immune status are two special characteristics of most AH though reasons are ill understood. So, mycological investigations are to be done for every such case.

Primary adrenal tuberculosis infection in patients with Behcet's disease presenting as isolated adrenal metastasis by 18F-FDG PET/CT: a rare case report and literature review

Primary adrenal tuberculosis (TB) is a rare type of extrapulmonary tuberculosis (EPTB). A pathological biopsy is usually required to make a definite diagnosis due to nonspecific symptoms. Antituberculous chemotherapy is the main treatment regimen, and cortisol replacement therapy should be added when adrenal insufficiency is involved. Here, we present a 59-year-old man who had recurrence of oral and genital aphthosis for 3 years and was diagnosed with Behcet's disease (BD), which was cured by thalidomide. After 10 days of admission, the patient had sudden abdominal pain in the right upper quadrant with high fever and was diagnosed with acute cholecystitis attack, which was treated by percutaneous transhepatic gallbladder drainage (PTGBD). Further contrast-enhanced CT showed a right adrenal mass with a diameter of 2.0 cm, and PET-CT indicated intense ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) uptake in the right adrenal mass with a maximum standardized uptake value (SUV_max) of 15.2. As a metastatic adrenal mass was suspected, the patient underwent retroperitoneal laparoscopic adrenalectomy. Histopathological and immunohistochemical analysis revealed primary adrenal TB. After routine anti-tuberculosis treatment with isoniazid, rifampin, pyrazinamide and ethambutol for six months, the patient was cured and discharged. In summary, primary unilateral adrenal TB without adrenal insufficiency is difficult to diagnose only on the basis of clinical manifestations and examinations. Further studies are needed to develop an easier and more accurate diagnostic examination.

A novel pipeline for adrenal tumour segmentation

BACKGROUND AND OBJECTIVE

Adrenal tumours occur on adrenal glands surrounded by organs and osteoid. These tumours can be categorized as either functional, non-functional, malign, or benign. Depending on their appearance in the abdomen, adrenal tumours can arise from one adrenal gland (unilateral) or from both adrenal glands (bilateral) and can connect with other organs, including the liver, spleen, pancreas, etc. This connection phenomenon constitutes the most important handicap against adrenal tumour segmentation. Size change, variety of shape, diverse location, and low contrast (similar grey values between the various tissues) are other disadvantages compounding segmentation difficulty. Few studies have considered adrenal tumour segmentation, and no significant improvement has been achieved for unilateral, bilateral, adherent, or noncohesive tumour segmentation. There is also no recognised segmentation pipeline or method for adrenal tumours including different shape, size, or location information.

METHODS

This study proposes an adrenal tumour segmentation (ATUS) pipeline designed to eliminate the above disadvantages for adrenal tumour segmentation. ATUS incorporates a number of image methods, including contrast limited adaptive histogram equalization, split and merge based on quadtree decomposition, mean shift segmentation, large grey level eliminator, and region growing.

RESULTS

Performance assessment of ATUS was realised on 32 arterial and portal phase computed tomography images using six metrics: dice, jaccard, sensitivity, specificity, accuracy, and structural similarity index. ATUS achieved remarkable segmentation performance, and was not affected by the discussed handicaps, on particularly adherence to other organs, with success rates of 83.06%, 71.44%, 86.44%, 99.66%, 99.43%, and 98.51% for the metrics, respectively, for images including sufficient contrast uptake.

CONCLUSIONS

The proposed ATUS system realises detailed adrenal tumour segmentation, and avoids known disadvantages preventing accurate segmentation.

What, where and why: exploring fluorodeoxyglucose-PET's ability to localise and differentiate infection from cancer

PURPOSE OF REVIEW

To review the utility of FDG-PET imaging in detecting the cause of fever and infection in patients with cancer.

RECENT FINDINGS

FDG-PET has been shown to have high sensitivity and accuracy for causes of neutropenic fever, leading to higher diagnostic certainty in this group. Recent advances in pathogen-specific labelling in PET to identify Aspergillus spp. and Yersinia spp. infections in mice, as well as differentiating between Gram-positive, Gram-negative and mycobacterial infections are promising.

SUMMARY

Patients with cancer are vulnerable to infection and fever, and the causes of these are frequently unclear using conventional diagnostic methods leading to high morbidity and mortality, length of stay and costs of care. FDG-PET/CT, with its unique complementary functional and anatomical information as well as its whole-body imaging capability, has demonstrated use in detecting occult infection in immunocompromised patients, including invasive fungal and occult bacterial infections, as well as defining extent of infection. By demonstrating disease resolution following treatment and allowing earlier cessation of therapy, FDG-PET acts as a key tool for antimicrobial and antifungal stewardship. Limitations include at times poor differentiation between infection, malignancy and sterile inflammation, however, exciting new technologies specific to infectious pathogens may help alleviate that issue. Further prospective randomised research is needed to explore these benefits in a nonbiased fashion.

18F-FDG PET/CT imaging and PET-guided biopsy in evaluation and treatment decision in adrenal histoplasmosis

Histoplasmosis is a rare opportunistic fungal infection. It is commonly seen in immunocompromised individuals from endemic areas. Adrenal glands are frequently involved in the disseminated disease. Here, we present the case of a retropositive patient with constitutional symptoms, where whole-body positron emission tomography/CT scan revealed intense ¹⁸F-fludeoxyglucose uptake in bulky adrenal glands, and subsequent positron emission tomography-guided biopsy helped in establishing the diagnosis of adrenal histoplasmosis.

Metabolic and anatomic characteristics of benign and malignant adrenal masses on positron emission tomography/computed tomography: a review of literature

PET/CT with (18)F-fluorodeoxyglucose (FDG) or using different radiocompounds has proven accuracy for detection of adrenal metastases in patients undergoing cancer staging. It can assist the diagnostic work-up in oncology patients by identifying distant metastases to the adrenal(s) and defining oligometastatic disease that may benefit from targeted intervention. In patients with incidentally discovered adrenal nodules, so-called adrenal "incidentaloma" FDG PET/CT is emerging as a useful test to distinguish benign from malignant etiology. Current published evidence suggests a role for FDG PET/CT in assessing the malignant potential of an adrenal lesion that has been 'indeterminately' categorized with unenhanced CT, adrenal protocol contrast-enhanced CT, or chemical-shift MRI. FDG PET/CT could be used to stratify patients with higher risk of malignancy for surgical intervention, while recommending surveillance for adrenal masses with low malignant potential. There are caveats for interpretation of the metabolic activity of an adrenal nodule on PET/CT that may lead to false-positive and false-negative interpretation. Adrenal lesions represent a wide spectrum of etiologies, and the typical appearances on PET/CT are still being described, therefore our goal was to summarize the current diagnostic strategies for evaluation of adrenal lesions and present metabolic and anatomic appearances of common and uncommon adrenal lesions. In spite of the emerging role of PET/CT to differentiate benign from malignant adrenal mass, especially in difficult cases, it should be emphasized that PET/CT is not needed for most patients and that many diagnostic problems can be resolved by CT and/or MR imaging.

18F-FDG PET as a monitoring tool to assess treatment response in bilateral adrenal histoplasmosis

A 60-year-old woman with clinical and biochemical features suggestive of adrenal insufficiency was found to have bilateral adrenal masses on CT scan and was subjected to F-FDG PET scan. The scan showed hypermetabolic mediastinal nodes in addition to intense tracer uptake in bilateral adrenal masses. CT-guided adrenal biopsy grew Histoplasma capsulatum on Sabouraud dextrose agar culture. A second F-FDG PET scan after 6 months of appropriate antifungal therapy showed a significant decrease in intensity of uptake consistent with the clinical outcome.