|Year : 2017 | Volume
| Issue : 2 | Page : 60-62
Giant adrenal myelolipoma: A rare case report and review of literature
Rajeev Sen, Sumiti Gupta, Padam Parmar, Komal Brar, Meenu Gilotra, Veena Gupta
Department of Pathology, PT BDS PGIMS, Rohtak, Haryana, India
|Date of Web Publication||20-Jun-2017|
Department of Pathology, PT BDS PGIMS, Rohtak - 124 001, Haryana
Source of Support: None, Conflict of Interest: None
Myelolipomas are a rare benign variant of adipose tissue tumors with additional hematopoietic elements. In general, these tumors were discovered accidentally on autopsy with a low incidence. Adrenal gland is the most common site for myelolipoma. We reported a case of giant adrenal myelolipoma (>18 cm) which presented with vague, nonspecific pain which is worth mentioning because of its rarity and huge size.
Keywords: Adrenal gland, giant, lipoma, myelolipoma
|How to cite this article:|
Sen R, Gupta S, Parmar P, Brar K, Gilotra M, Gupta V. Giant adrenal myelolipoma: A rare case report and review of literature. J Integr Nephrol Androl 2017;4:60-2
|How to cite this URL:|
Sen R, Gupta S, Parmar P, Brar K, Gilotra M, Gupta V. Giant adrenal myelolipoma: A rare case report and review of literature. J Integr Nephrol Androl [serial online] 2017 [cited 2020 Jul 5];4:60-2. Available from: http://www.journal-ina.com/text.asp?2017/4/2/60/208578
| Introduction|| |
Myelolipoma is a rare variant of lipoma composed of mature adipose tissue along with hematopoietic elements. In general, these tumors were discovered accidentally on autopsy with a low incidence varying from 0.08% to 0.4%. With advance in noninvasive imaging modalities, these tumors are found more frequently. This lesion is mostly located in adrenal glands, but has been found at extra-adrenal sites also such as pelvis, retroperitoneum, and thorax. Most of these tumors are small (<5 cm) and hormonally inactive; however, large-sized tumors can present with hemorrhagic complications.
| Case Report|| |
A 55-year-old male presented to surgery department with complaints of nonspecific back pain and swelling in the right flank region for the last 2 years, slowly increasing in size. Abdominal examination revealed palpable diffuse swelling in the right lumbar region. All hematological and biochemical investigations were normal. Ultrasound abdomen revealed a mass of variable echogenic in the right suprarenal region of size 20 cm × 16 cm × 12 cm. Abdominal computed tomography (CT) scan showed a well-defined mass lesion in the right adrenal region of size 19 cm × 16 cm × 11 cm with a prominent negative fatty attenuation. Workup for hormonal status showed normal results (cortisol - 16 mcg/dL and ACTH - 45 pg/mL). A provisional diagnosis of primary adrenal malignant tumor was made. The patient underwent right adrenalectomy and his postoperative recovery period was uneventful. On gross examination, a well-circumscribed gray-yellow nodular mass measuring 18 cm × 16 cm × 11 cm was received in pathology department for histopathological examination [Figure 1]. On serial sectioning, gray-yellow to gray-brown areas were identified along with extensive hemorrhagic areas [Figure 2]. Microsections revealed varying proportion of mature adipose tissue admixed with hematopoietic elements along with extensive areas of hemorrhage and necrosis [Figure 3]. On extensive sampling with multiple sections from the mass, it revealed peripheral compressed adrenal gland [Figure 4]. The final diagnosis of adrenal myelolipoma was made. Due to low fatty content with hemorrhages and larger size, the exact nature of adrenal mass was not made on initial radiological examination. The patient was followed up for 6 months postoperatively and was healthy.
|Figure 3: H and E section from adrenal mass revealing mature fat with hematopoietic elements (×200)|
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|Figure 4: H and E section showing compressed normal adrenal gland tissue in periphery with mature fat with hematopoietic elements (×200)|
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| Discussion|| |
Myelolipoma was first described in 1905. “Formations myelolipomatoses” term was given by Oberling to this tumor in 1929. Myelolipomas are rare benign adipose tissue tumors with additional hematopoietic elements. The most common site is adrenal gland and less commonly at extra-adrenal sites including the pelvis, mediastinum, and retroperitoneum. Myelolipomas generally occur between 50 and 70 years of age and have no sex predilection.,
Various hypotheses have been put forward to explain the etiology of myelolipomas, yet it is unclear. According to a new theory, it is believed that adrenal myelolipoma originates from metaplasia of reticuloendothelial cells in adrenal capillaries or from undifferentiated stromal cells in the zona fasciculate of the adrenal cortex whereas some believe that these tumors arise from embryonic cells of bone marrow that embolize to adrenal gland. However, some authors believe it to be the result of endocrine stimulation, stressful and unbalanced lifestyle, and chronic systemic diseases. They can also be found in association with obesity, hypertension, and a variety of chronic diseases.
In the past, incident rates of these tumors ranged from 0.08% to 0.4% during autopsy. These tumors constitute 4%–5% all primary adrenal tumors. Myelolipomas are generally <4 cm in diameter, but can attain big sizes as well. Tumors of size more than 8 cm are referred to as giant myelolipoma., They present as unilateral masses mainly, however bilateral cases have been reported. Smaller myelolipomas are usually asymptomatic. Large adrenal myelolipomas may complicate into spontaneous retroperitoneal hemorrhage rarely. Myelolipomas are hormonally inactive, however these tumors can be associated with congenital adrenal hyperplasia, Cushing syndrome, and rarely with pheochromocytoma, Conn syndrome, and adrenal insufficiency.,
Myelolipomas are also known as incidentalomas and are discovered on imaging for unrelated reasons or during autopsy. The appearance of myelolipoma on imaging depends on the fat content of the lesion. On ultrasonography, myelolipoma is hyperechoic if fat is the main component and hypoechoic if myeloid cells are prominent. Computed tomography shows hypodense nonenhancing lesion with negative attenuation values, suggestive of fat that is <−30 Hounsfield units. On magnetic resonance imaging, fat shows high signal intensity on both T1 and T2 weighted sequences.,
Grossly, myelolipomas are well circumscribed but rarely encapsulated. They can show yellow to deep brown color depending on the relative composition of fat and bone marrow elements. The surrounding adrenal gland is normal in appearance or compressed. Microscopically, adrenal myelolipoma is composed of a variable mixture of fat and hematopoietic elements. Differential diagnoses for fat-containing adrenal masses include lipoma, liposarcoma, angiomyolipoma, extramedullary hematopoiesis, and adenoma. Extramedullary hematopoiesis (EMH) is ruled out with the absence of hepatosplenomegaly, hematological and skeletal abnormalities. In EMH, fat is overrunning the poorly circumscribed tumor, whereas in myelolipoma, fat is integral to tumor. In our case, adrenal mass was larger in size with poor fatty content. On radiological examination with a rare presentation of mass, the exact nature of mass was not defined by radiologist.
There is no general consensus for the management of adrenal myelolipoma. However, at present, small and asymptomatic myelolipomas (<5 cm) are managed conservatively to avoid lifelong steroid replacement with a yearly follow-up with CT. Large (>5 cm) or symptomatic lesions should be surgically resected because of the risk of malignant change and spontaneous rupture leading to retroperitoneal bleed. Laparoscopic management is also on rise, but for tumors >10 cm in size or including adhesions and infiltration into the surrounding structure, it is not indicated.
| Conclusion|| |
Due to the rarity of adrenal myelolipoma and presentation of mass with low-fat content, the exact nature of mass was not defined preoperatively using imaging technique. Surgeons and pathologists must be well aware of this entity which is completely curable by adrenalectomy alone.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understand that his name and initial will not be published and due efforts will be made to conceal his 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]