|Year : 2018 | Volume
| Issue : 1 | Page : 44-46
Adrenal myelolipoma: Radiologic-pathologic correlation
Ashish Sachan1, Hirdaya Hulas Nag1, Sandip Barmann2, Ravindra Kumar Saran2
1 Department of GI Surgery, GB Pant Hospital, New Delhi, India
2 Department of GI Pathology, GB Pant Hospital, New Delhi, India
|Date of Web Publication||2-Apr-2018|
Hirdaya Hulas Nag
Department of GI Surgery, Room No 220, Academic Block, GB Pant Hospital, New Delhi
Source of Support: None, Conflict of Interest: None
Myelolipomas are rare, benign tumors of adrenal gland. These tumors are generally asymptomatic and are diagnosed incidentally. Differentiating the tumor from other adrenal tumors such as liposarcoma, pheochromocytoma is important for management. We hereby describe the case of adrenal myelolipoma we recently managed, with emphasis on the radiologic and pathologic correlation of this rare disease.
Keywords: Adrenal gland, adrenal incidentaloma, adrenal myelolipoma
|How to cite this article:|
Sachan A, Nag HH, Barmann S, Saran RK. Adrenal myelolipoma: Radiologic-pathologic correlation. Apollo Med 2018;15:44-6
| Introduction|| |
Adrenal myelolipoma is a rare, nonfunctioning, and benign tumor. Most lesions are small and asymptomatic, discovered incidentally at autopsy or on imaging studies performed for other reasons., In view of their rarity, they are usually detected incidentally or misdiagnosed. We describe a case of adrenal myelolipoma and review the literature on its clinical features, diagnosis, and management.
| Case Report|| |
A 40-year-old male was admitted with chief complaints of dull aching pain in the right side of the abdomen for 1 month. There was no history of jaundice, anorexia, weight loss, altered bladder, or bowel habits. On per abdomen examination, no lump or organomegaly was found.
Ultrasonography of abdomen was done which showed a 10 cm × 10 cm echogenic lesion with fat attenuation in the retroperitoneum abutting liver and right kidney. Due to fat density in the lesion, a possibility of angiomyolipoma, lipoma, or liposarcoma was raised on ultrasound. Contrast-enhanced computed tomography (CT) abdomen was done which showed a large (9.4 cm × 9.3 cm × 9 cm) well-defined hypodense lesion with predominant fat attenuation with mixed isodense areas in the lesion, in right retroperitoneal region. No significant postcontrast enhancement or calcification was seen. Right adrenal gland could not be identified separately and a possibility of retroperitoneal/adrenal liposarcoma was suggested. Lesion was displacing duodenum, head of pancreas, and indenting inferior vena cava (IVC) [Figure 1] and [Figure 2].
|Figure 1: Contrast-enhanced computed tomography scan image showing mass lesion indenting head of pancreas and inferior vena cava|
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|Figure 2: Contrast-enhanced computed tomography scan image showing mass lesion displacing duodenum, head of pancreas, and indenting inferior vena cava (arrow)|
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The patient was not hypertensive; there was no history of palpitations. Vanillylmandelic acid and metanephrine were normal. All routine laboratories were also normal. Considering the possibility of liposarcoma suggested on CT scan, large size, and symptomatic nature of the lesion, surgical excision of the lesion was planned. Laparoscopic-assisted excision of tumor was performed. Intraoperatively, a 10 cm × 10 cm mass lesion arising from right suprarenal region abutting IVC was identified. Histopathology report showed a well-circumscribed tumor [Figure 3] composed of mature adipose tissue, myeloid cells along with megakaryocytes [Figure 4] and [Figure 5]. Bony metaplasia is seen [Figure 4] and [Figure 5]. Edge of tumor shows normal adrenal tissue and a histopathological diagnosis of adrenal myelolipoma was made. The patient is symptom free 6 months after surgery with no recurrence.
|Figure 5: Histopathology slide (×600) showing erythroid and myeloid precursors|
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| Discussion|| |
Myelolipomas are rare, benign tumors of adrenal gland. Adrenal myelolipomas constitute for approximately 3 to 5% of all the primary adrenal tumors. It comprises of benign mature adipose tissue and normal hematopoietic cells. These tumors are generally benign, asymptomatic and are usually diagnosed incidentally. Due to increase in use of contrast-enhanced CT scan (CECT) and magnetic resonance imaging (MRI) abdomen, these lesions are more commonly detected. Detection of AML, among other adrenal incidentalomas such as liposarcoma, pheochromocytoma, and fat-containing adrenocortical carcinoma, is important for management. Surgical treatment is indicated when these tumors are large in size (>6 cm) and/or symptomatic in nature., For larger tumors, surgical excision is warranted to avoid rupture of tumor and hemorrhage from the lesion.
CT and MRI are effective in diagnosing adrenal myelolipomas in more than 90% of cases., On CECT, appearance is usually characteristic. Appearance of AML depends on its composition, as fatty component is usually variable. Fatty mass lesion of −30 HU attenuation (may range up to 100 HU) interspersed with higher attenuation marrow elements is seen. Small punctuate calcifications may be identified in 25%–30% of cases. In cases of hemorrhage, higher attenuation may be seen. Adrenal adenomas may appear as low-density lesions (with attenuation values <18 HU); however, they are more dense and homogeneous than myelolipomas. Liposarcomas generally show an infiltrative pattern with attenuation coefficients up to +30 HU.
On MRI abdomen, on T1-weighted image, lesion is typically hyperintense due to fat contents, typically shows fat suppression. On T2-weighted image, lesion is generally intermediate to hyperintense. On gadolinium contrast-enhanced imaging, it shows striking enhancement. During in and out phase in masses with mixed components, out-of-phase imaging may demonstrate signal loss (as fat cells usually have less intracellular water)., In cases where imaging findings are inconclusive or a suspicion of malignancy is present, a percutaneous biopsy can be performed and surgical resection is indicated.
For surgical approach, extraperitoneal approach is preferred over transperitoneal approach, due to early recovery and few postoperative complications. Extraperitoneal approach is not preferred for tumors >10 cm in size. Laparoscopic management of these tumors is also reported in literature.
AML specimen grossly shows a well-defined, rounded mass lesion containing yellow adipose tissue, variegated appearance with varying amount of red-brown hematopoietic elements. Microscopic examination shows islands of hematopoietic cells with mature adipocytes. Occasionally, hemorrhage, calcification, necrosis, and very rarely, bony island may be identified.
| Conclusion|| |
Adrenal myelolipomas are rare, benign tumors. Establishing the diagnosis and ruling out other differential diagnosis is vital for patient management. Small asymptomatic lesions can be managed expectantly whereas surgical excision is indicated for larger and symptomatic lesions.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]