Adrenal myelolipoma

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: ; Roukoz A. Karam, M.D.[2]

Synonyms and keywords:

Historical Perspective

Adrenolipoma was first discovered by Gierke in 1905.

Classification

Myelolipomas are classified into 4 type based on their clinicopathologic patterns:

• Isolated adrenal myelolipoma
• Adrenal myelolipoma with acute hemorrhage
• Extra-adrenal myelolipoma
• Myelolipoma associated with other adrenal diseases.

Clinicopathologic patterns	Description	Symptoms
Isolated Adrenal Myelolipoma	Myelolipomas occurring in an otherwise normal adrenal gland Most common pattern of presentation	Asymptomatic Incidentally identified
Adrenal Myelolipoma with Acute Hemorrhage	Isolated larger lesions (typically over 4 cm in size)	Retroperitoneal hemorrhage
Extra-adrenal Myelolipoma	Myelolipomas occurring outside the adrenal gland Retroperitoneum (presacral or perirenal)	Patients usually have no endocrine disorder or acute haemorrhage.
Adrenal Myelolipoma with Associated Adrenal Disease	Associated with endorcrine disorder Hypercortisolism (Cushing syndrome) and 21-hydroxylase deficiency with adrenal hyperplasia	Reported to present with an underlying endocrine disorder.

Pathophysiology

• Myelolipomas are usually less than 4 cm in size occasionally measuring more than 10 cm in size.
• Extra-adrenal sites for myelolipomas include the retroperitoneum, thorax, and pelvis.
• Usually unilateral however they can also involve both adrenals.
• One hypothesis suggests that stimuli, such as necrosis, inflammation, infection, or stress could cause adrenocortical cell metaplasia
• If chronically present these stimulants lead to the development of neoplasms.
• This hypothesis is supported by the increased incidence of the lesion in the advanced years of life
• On gross pathologic examination, a cut section of a myelolipoma has a variegated appearance consisting of bright yellow areas of fat, dark red areas of hematopoietic myeloid tissue, and areas with intermixed red and yellow components.
• On histopathologic examination, myelolipomas are predominantly composed of fatty areas with interspersed hematopoietic tissue components.
  • • These fatty elements and hematopoietic areas may be clearly separated, or they are often intermixed.
    • Tissue analysis often reveals a variable amalgamation of myeloid and erythroid cells, megakaryocytes, and occasionally lymphocytes.
    • In an isolated adrenal myelolipoma, a peripheral rim of normal adrenal cortical tissue can be commonly identified distinctly from the mass.
    • Rarely the myelolipomas can contain osteoid tissue in addition to the myeloid tissue.
    • The hemorrhagic areas may be partly replaced by fibrotic tissue or may undergo calcification
      

Causes

The exact causes of Adrenal myelolipoma remain unknown. However, Adrenal myelolipoma is often associated with conditions that can be considered as adrenal stimulants such as:

• Cushing's disease
• Obesity
• Hyperlipidemia
• Hypertension
• Diabetes
• Stressful lifestyle
• Unbalanced diet

Epidemiology and Demographics

• The incidence of adrenolipoma is approximately 0.8-4 per 100,000 individuals worldwide.
• Adrenolipoma affects men and women equally.
• Adrenolipomas are usually recognized in adults, either incidentally at ultrasound or computed topography or may present with vague abdominal symptoms if complicated by hemorrhage.

Risk Factors

There are no established risk factors for Adrenal myelolipoma.

Screening

There is insufficient evidence to recommend routine screening for Adrenal myelolipoma.

Diagnosis

Diagnostic Study of Choice

The diagnosis of Adrenal myelolipoma is made when

History and Symptoms

The majority of patients with Adrenal myelolipoma are asymptomatic.

Physical Examination

Common physical examination findings of Adrenal myelolipoma include

Electrocardiogram

There are no ECG findings associated with Adrenal myelolipoma.

X-ray

There are no x-ray findings associated with Adrenal myelolipoma.

Echocardiography or Ultrasound

There are no echocardiography/ultrasound findings associated with Adrenal myelolipoma.

CT scan

Abdominal CT scan may be helpful in the diagnosis of Adrenal myelolipoma. Findings on CT scan suggestive of/diagnostic of Adrenal myelolipoma include

MRI

There are no MRI findings associated with Adrenal myelolipoma.

Other Imaging Findings

There are no other imaging findings associated with Adrenal myelolipoma.

Other Diagnostic Studies

There are no other diagnostic studies associated with Adrenal myelolipoma.

Treatment

Medical Therapy

There is no treatment for Adrenal myelolipoma; the mainstay of therapy is supportive care.

Surgery

Surgery is not the first-line treatment option for patients with Adrenal myelolipoma. Surgery is usually reserved for patients with either

Primary Prevention

There are no established measures for the primary prevention of Adrenal myelolipoma.

Secondary Prevention

There are no established measures for the secondary prevention of Adrenal myelolipoma.