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JBRBTR, 2008, 91: 90-91.

BILATERAL ADRENAL MYELOLIPOMAS

K. Civrilli, N. Damry, R. Stepp, A. Efira, J. Mathieu1

Key-word: Myelolipoma

Background: A 28-year-old male patient presented with bilateral inguinal adenopathies, painfulat the left. His medical history revealed a treated pulmonary tuberculosis. At the time of presen-tation chest radiography was normal. Except for the inguinal adenopathies, physical examina-tion was unremarkable. Laboratory tests showed hypokalemia, inflammation and anemia.

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B C

A B1A

Fig. 1B 1C

2A 2B1. Department of Radiology, University Hospital Brugmann, Brussels, Belgium

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BILATERAL ADRENAL MYELOLIPOMAS CIVRILLI et al 91

Work-up

CT scan of the abdomen (Fig. 1), unenhanced CTscan at inguinal level (A) shows bilateral inguinaladenopathies, more prominent on the left side.Unenhanced CT scan at upper abdominal level (B)

demonstrates the presence of bilateral adrenalmasses with central areas of fat density. Contrast-enhanced CT scan at upper abdominal level (C)shows pronounced enhancement at the peripheryof the adrenal masses bilaterally.

MRI at upper abdominal level (Fig. 2) includes anaxial T1-weighted image (A) which shows high sig-nal intensity centrally in both the adrenal masses,more pronounced at the left side and a fat-sup-pressed T1-weighted image (B) demonstratingcomplete signal void in the central part of theadrenal masses.

Imaging findings consist of multiple intra-

abdominal lymph nodes, bilateral adrenal massesand inguinal lymph nodes. The left inguinal lymphnodes presented as a necrotic mass. Biopsy of theleft inguinal nodes was diagnostic for a malignantnon-Hodgkin lymphoma with large B-cells.

Radiological diagnosis

Based on CT- and MR-imaging findings (fat den-sity on CT scan, high intensity on T1-WI andabsence of signal on fat suppressed MR-images)the presence of coexistent bilateral adrenalmyelolipomas, as incidental finding, was suggest-ed. Follow-up after chemotherapy over a two-year

period, revealed that the inguinal lymph nodes haddisappeared, but the bilateral adrenal massesremained unchanged, thereby confirming the initialradiological diagnosis.

Discussion

Adrenal myelolipoma is a rare benign neoplasmcomposed of myeloid, erythroid, and fatty elementswith occasional calcifications. The incidence variesfrom 0,08 to 0,4% at autopsy. The male-to-femaleratio is 1:1 and the lesions most commonly occur inthe fifth to seventh decade of life. Most lesions are

small and asymptomatic, discovered incidentally atautopsy or on imaging studies performed for otherreasons. Tumor size varies from several millimetresto larger than 30 cm. Most myelolipomas are unilat-eral but show no predilection to one particular side,they are hormonally nonfunctional and do notundergo malignant transformation.

The imaging appearance of myelolipomas isbased on the fat content of the lesion: thus theyappear echogenic at US, with low attenuation at CTscan. The presence of pure fat within an adrenal

lesion at CT is diagnostic of a myelolipoma, and nofurther work-up is required.

With MR-imaging, the fatty portion of the lesionis hyperintense on T1-weighted images. This is non-specific and can also be seen in any lesion that con-tains hemorrhage. Therefore, it is necessary to per-

form a frequency-selective fat-suppressed T1-weighted sequence and compare it with the non-fat-suppressed T1-weighted sequence. The fattyportion of the lesion should lose signal on the fat-suppressed sequence, and is diagnostic of amyelolipoma.

In the presented case, the patient had no symp-toms related to the adrenal masses, although theirsubstantial size and mass-effect exerted on thekidneys. They were bilateral, nonfunctional andcontained no calcifications nor hemorrhagic areas.

As they met the CT and MRI diagnostic criteriafor adrenal myelolipoma, the radiologist felt confi-

dent about the diagnosis, thereby avoiding biopsyof these lesions.The differential diagnosis that might have been

considered includes retroperitoneal liposarcoma,adrenal lymphoma, adrenal metastases and adrenaladenoma. The hyperintense aspect on T1-weightedin-phase MR-images, excluded adrenal lym-phomas and metastases, that both have low signalon T1-weighted in-phase MR-images. There was noevidence of liposarcoma, because the sclerosingcomponents of liposarcoma are predominantly ofmuscle-density although fatty components alsomay be present.

Adrenal adenomas show only minor enhance-

ment following administration of gadolinium,whereas the myelolipomas enhance strongly.

To our knowledge, there are very few other reportsof patients, presenting a combination of bilateraladrenal myelolipomas and non Hodgkin lymphoma.CT and/or MRI are very useful for the differentialdiagnosis and can obviate the need for biopsy.

Bibliography

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