Case report. Combined adrenal adenoma and myelolipoma

Imaging characteristics of pathologically proven adrenal adenomas with myelolipomatous degeneration: correlation with clinical and pathologic features

OBJECTIVES

Adrenal adenoma with myelolipomatous degeneration (AMD) is a rarely reported and often overlooked entity. The aim of this study is to improve understanding of these lesions by characterizing the imaging findings with pathologic and clinical correlation.

METHODS

In the largest series to date, we report 11 nodules in 11 patients confirmed with a pathologic diagnosis of AMD. The available cross-sectional imaging and histopathologic features were reviewed by two radiologists and two pathologists, respectively. Clinical and laboratory data for each patient were obtained from the electronic medical records, when available.

RESULTS

All 11 patients had a CT prior to resection or biopsy of the adrenal nodule, with five having received an adrenal mass protocol study. An MRI was available in three patients. The median size of the nodules on imaging was 4.5 cm (range 2.8-8.7) and all but one had macroscopic fat. The largest focus of macroscopic fat had a median size of 0.7 cm (range 0.2-1.6) and on average was 14.4% the size of the tumor, using greatest dimensions. Four (36.4%) patients had a diagnosis of Cushing syndrome prior to nodule resection.

CONCLUSIONS

Not all adrenal nodules with macroscopic fat on imaging are pure myelolipomas. An AMD should be considered, especially if the foci of fat are small and other features of an adenoma are present. Some may also be associated with Cushing syndrome.

ADVANCES IN KNOWLEDGE

Myelolipomatous degeneration within an adrenal adenoma has only rarely been previously reported with very few reports emphasizing the imaging features. There may be an association with cortisol hypersecretion and improved recognition of this entity could lead to changes in clinical management.

Adrenal myelolipoma associated with adenoma

The association of an adrenal myelolipoma with a non-functioning adenoma is very rare. Herein, we report on such a case in an asymptomatic 64-year-old woman. To the best of our knowledge, there is only one other case of non-functioning adrenocortical adenoma associated with myelolipoma in the same gland. Furthermore, only two other adenomas (mineral corticoids and corticosteroid producing tumors) associated with myelolipomas have been reported, and both myelolipomas were less than 1 cm in size. In conclusion, the 8.5 cm myelolipoma in our case is the largest compared with the three previously reported ones.

Non-functional adrenocortical adenoma with extensive degeneration

We report a case of non-functional adrenocortical adenoma of 5.5 x 5.5 x 3.2 cm in size that had an unusual histopathological appearance in two respects. First, the tumor contained small adipose foci with osteogenesis and was suspected of being a myelolipoma based on its appearance on computerized tomography (CT) and magnetic resonance imaging. However, pathologically, the fat element was seen focally and was not accompanied by hematopoietic cells, and the diagnosis of myelolipoma was abandoned. Second, the tumor was suspected of being an adrenal carcinoma based on its appearance on CT scans and showed extensive degeneration: fibrosis, hemorrhage, loss of parenchyma and moderate atypism of the tumor cells. However, as the architecture of the tumor cells was non-diffuse and there were no necrotic foci or mitoses, and vascular or capsular invasion were not present, the tumor was concluded to be an adrenocortical adenoma rather than a carcinoma. We diagnosed the tumor as a non-functional adrenocortical adenoma with extensive degeneration as the extensive areas of fibrosis were particularly remarkable. Furthermore, the extensive areas of degeneration might have been caused not only by an ischemic effect but also by low hormone levels.

Large degenerated adrenal adenomas: radiologic-pathologic correlation

PURPOSE

To correlate the radiologic and pathologic findings and differential diagnosis of large, degenerated adrenal adenomas.

MATERIALS AND METHODS

The authors reviewed the radiologic and pathologic characteristics of 30 large adenomas with cystic regions or areas of heterogeneity that were either intrinsic or demonstrated at contrast material-enhanced computed tomography (CT) or magnetic resonance (MR) imaging. Images of 24 adrenocortical carcinomas were also reviewed to determine whether differentiating characteristics existed.

RESULTS

Most of the adrenocortical adenomas were in asymptomatic women. Ten adenomas contained calcification. Pathologic examination revealed good correlation between heterogeneity and liquefied regions. Histologic examination confirmed regions of adenomatous tissue with areas of hemorrhage, amorphous degenerated material, calcification, and fibrosis. Some tumors contained myelolipomatous foci. Although some clinical and imaging findings differed between the groups, no features could be found that enabled the radiologic differentiation of adenomas from carcinomas.

CONCLUSION

A subgroup of adrenal adenomas are larger, more heterogeneous, and more frequently calcified than those with the usual imaging findings. Central necrosis, hemorrhage, or both are responsible for many of the imaging features. Differentiation of these lesions from other large adrenal masses, including adrenal carcinoma, cannot be made by means of imaging alone; resection is required for the definitive diagnosis.

Adrenocortical adenoma containing a fat component: CT and MR image evaluation

A case of adrenocortical adenoma containing small adipose foci is presented. A small amount of fat within the mass led to an erroneous preoperative diagnosis of myelolipoma. Adrenal adenoma should be included in the differential diagnosis of adrenal mass containing fat.

Adrenal myelolipomas: CT appearance with tiny amounts of fat and punctate calcification

Five cases of myelolipoma of the adrenal are presented which contained only tiny foci of fat along with areas of punctate calcification. This computed tomographic (CT) appearance is less common for this neoplasm and has only been described in three of 26 previously published CT cases of this adrenal tumor. The presence of even tiny amounts of fat in an adrenal mass should alert the radiologist to the probable diagnosis of myelolipoma. Small foci of calcification are also frequently associated.

Adrenal myelolipoma: a case report and review of the literature

A case of a 73 year old man who was preoperatively diagnosed as possibly having myelolipoma is presented herein. Adrenal myelolipoma is an uncommon benign tumor of which only 74 foreign cases and 43 Japanese cases have been previously reported in the literature dealing with surgically removed myelolipomas. The most consistent complaint of the adrenal myelolipoma sufferer is abdominal pain, caused by hemorrhaging in the tumor, and many cases are associated with obesity, hypertension and/or diabetes mellitus. There is now an increasing number of such cases being diagnosed during abdominal scanning with ultrasonography or computerized tomography for unrelated problems, whereupon the myelolipoma is usually surgically resected. With the availability of modern scanning techniques and fine needle biopsy, however, it should be possible to adopt a more conservative approach to the management of asymptomatic adrenal myelolipoma. Nevertheless, symptomatic or large tumors, must be removed since there is a high risk of spontaneous hemorrhage.

Adrenal myelolipoma discovered incidentally on abdominal CT and MR imaging

This report describes an adrenal myelolipoma occurring in a 39-year-old man first noted incidentally by computed tomography (CT). The radiographic findings of this neoplasm are briefly discussed and magnetic resonance (MR) imaging of myelolipoma is also described. Myelolipomas can be distinguished from nonfunctioning adenomas by differences in signal intensity on T2-weighted images.

Adrenal myelolipoma: clinical, radiologic, and histologic features

The adrenal myelolipoma is a benign, endocrinologically inactive tumor whose histologic structure consists of mature adipose tissue with foci of hematopoietic cells. A case is presented of a seventy-one-year-old woman in whom the diagnosis was established preoperatively by means of sonography, computerized tomography, and magnetic resonance tomography. In a review of the literature, the radiologic profile is discussed, and based on the analysis of 59 surgically treated cases a therapy recommendation is given.

Serendipitous adrenal masses: prevalence, significance, and management

Over a 2 year period, 63 of 1,459 patients examined by computerized tomography were found to have adrenal masses. In 19 patients (1.3 percent of patients examined and 30 percent of patients with adrenal masses), they were unexpected and did not give rise to symptoms or signs. Three patients were explored. Two of the patients had adrenocortical adenomas and a third, a ganglioneuroma. Adrenal function tests were performed in 14 patients and showed evidence of Cushing's syndrome in 1 patients and revealed no abnormalities in 13. The lesions in 10 of 11 nonsurgical patients followed by computerized tomography for 11 to 36 months showed no change. One lesion became significantly smaller. In a review of 988 autopsy reports, grossly visible adrenal masses were present in 73 patients (7.3 percent), including 19 adrenocortical adenomas (1.9 percent) and 50 metastases (5 percent). We conclude that serendipitous adrenal masses are usually small, nonfunctioning, and benign, the most common lesion being adrenocortical adenoma. A protocol has been suggested for management to identify the minority of patients with functioning or malignant lesions and to avoid unnecessary surgery in the others who have benign disease.

Adrenal myelolipoma: CT and ultrasound findings

The computed tomographic (CT) and ultrasound (US) appearances of 5 adrenal myelolipomas in 4 patients are reported. The component tissues of a myelolipoma determine its CT and US appearance. A myelolipoma consisting primarily of fat has a characteristic CT and US appearance. A myelolipoma also containing macroscopic quantities of nonfatty material (blood, calcium, or myeloid tissue) may have a nonspecific CT or US appearance if fat is not identified in the lesion. In equivocal cases, needle biopsy may be used to establish the diagnosis of myelolipoma.

Computed tomography and angiography in the evaluation of adrenal diseases

Computed tomography, adrenal venous blood sampling, phlebography and arteriography were compared as diagnostic methods in 50 proven cases of adrenal disease. The diagnostic accuracy was 90 per cent for CT, 100 per cent for adrenal venous sampling, 75 per cent for phlebography and 58 per cent for arteriography. It was necessary in some instances to correlate the findings for more than one modality to reach a correct diagnosis. From an analysis of the different examination methods a sequence in the radiologic evaluation of the pathologic adrenal gland is suggested. CT can be used to advantage as the primary imaging method. However, the other modalities, still play an important role.