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CASE REPORT
Year : 2019  |  Volume : 8  |  Issue : 3  |  Page : 225-228

Incidentally discovered adrenal mass: A study of two cases and review of literature


1 Department of Pathology, Bhaskar Medical College and General Hospital, Hyderabad, Telangana, India
2 Department of Pathology, PGIMER, Dr Ram Manohar Lohia Hospital, New Delhi, India

Date of Submission18-Nov-2018
Date of Acceptance04-Oct-2019
Date of Web Publication17-Oct-2019

Correspondence Address:
Dr. Ruchi Nagpal
Department of Pathology, Bhaskar Medical College and General Hospital, Hyderabad, Telangana
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/JDRNTRUHS.JDRNTRUHS_106_18

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  Abstract 


Adrenal myelolipoma is a rare tumor that is benign in nature, usually asymptomatic, unilateral, and nonsecreting. It is composed of variable mixture of mature adipose tissue and hematopoietic elements and develops within the adrenal gland. With the widespread use of cross-sectional imaging modalities such as ultrasonography (USG) and computed tomography (CT), the incidental detection of these tumors is increasing in frequency. We report two cases of adrenal myelolipoma in a 48-year-old female and a 47-year old male who presented with pain in the abdomen. Contrast-enhanced computed tomography scan of the abdomen revealed the possibility of myelolipoma. The patients were subjected to adrenalectomy and their postoperative course was uneventful. The histopathological evaluation of the mass confirmed the initial diagnosis of adrenal myelolipoma. Although mostly discovered as an “incidentaloma,” the diagnosis of adrenal myelolipoma requires thorough diagnostic study. Imaging techniques such as USG and CT scans as well as biochemical studies are useful for indicating the best treatment taking into account the size of the mass and possible hormone production. Surgical resection is advocated through extraperitoneal approach as it minimizes postoperative complications and leads to quicker recovery.

Keywords: Adrenal, computed tomography, myelolipoma


How to cite this article:
Nagpal R, Malhotra P. Incidentally discovered adrenal mass: A study of two cases and review of literature. J NTR Univ Health Sci 2019;8:225-8

How to cite this URL:
Nagpal R, Malhotra P. Incidentally discovered adrenal mass: A study of two cases and review of literature. J NTR Univ Health Sci [serial online] 2019 [cited 2019 Nov 13];8:225-8. Available from: http://www.jdrntruhs.org/text.asp?2019/8/3/225/269481




  Introduction Top


Adrenal myelolipoma is a rare urological lesion and is usually benign in nature. It is composed of mixture of mature adipose and hematopoietic elements. It was first described by Gierke in 1905 and later on termed as “myelolipoma” by Oberling in 1929.[1] Earlier, these lesions were detected at autopsy or in conditions where massive growth or an alteration in the hormonal production led to clinical presentation. However, nowadays, with the widespread use of noninvasive cross-sectional imaging modalities such as ultrasonography (USG), computed tomography (CT), and magnetic resonance imaging, incidental detection is more common.[2] Hence, it is also known as “incidentalomas.” Men and women are equally affected, and it is most commonly found between the fifth and seventh decades of life. They are usually nonsecreting, but overproduction of adrenal hormones is also described in some cases.[3]

Here, we describe two cases of incidental diagnosis of a large adrenal myelolipoma in patients who presented with upper abdominal pain and review the literature on its etiology, diagnosis, and management.


  Case Report Top


Case 1

A 48-year-old female presented with complaints of dull aching, intermittent, nonradiating abdominal pain since 20 days and also had history of hypertension. On physical examination, a lump was felt in the right lumbar fossa which was around 8 × 8 cm. The skin over the abdomen was normal and all the quadrants moved equally with respiration. Initial laboratory data including hemogram and biochemical analysis were within normal limit. Endocrinological tests and assay of urinary catecholamines did not show significant alterations. USG showed the presence of a hyperechoic mass with non-well-defined boundaries in the right suprarenal region. Contrast-enhanced computed tomography (CECT) revealed large well-defined soft-tissue density lesion involving right suprarenal location measuring 11 × 8 cm showing significant fat density, causing mass effect in the form of compression of posteroinferior surface of the liver anteriorly and abutting the right crus of the diaphragm posteriorly, likely to be adrenal myelolipoma [Figure 1]a.
Figure 1: (a) CT appearance of myelolipoma. Contrast-enhanced CT scan of the upper abdomen showing the large heterogeneous mass covering the upper right retroperitoneal space (arrows) with variable central and peripheral attenuation. (b) CECT showing heterogeneous fat-containing lesion in left adrenal measuring 6.4 × 4.7 × 3.3 cm

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Case 2

A 47-year-old male presented with dull-aching pain in the right flank region since 2 years which has been increased since the past 4 months. Pain was radiating to the right lumbar region and continuous in nature. History of burning micturition and urgency was present. On examination, there was no palpable lump. Mild tenderness was present in the lumbar region. Free metanephrine level was 77.0 pg/mL. USG showed the features suggestive of right-side multiloculated cystic lesion Bosniak type IIF/chronic focal hydronephrosis. CECT revealed multiloculated cystic lesion in the lower pole of the right kidney and heterogeneous fat-containing lesion measuring 6.4 × 4.7 × 3.3 cm in the left adrenal gland, suggesting the possibility of adrenal myelolipoma [Figure 1]b.

After a thorough preoperative workup, surgical right adrenalectomy was performed for both the patients through right subcostal incision for extraperitoneal approach of the adrenal gland. The masses were totally dissected from the upper pole of the kidney and sent for histopathological evaluation. Gross examination of the specimens revealed large, round, 11 × 9× 4.5 cm [Figure 2]a and 6.5 × 5× 2.5 cm encapsulated masses with smooth external surface weighing 675 and 384 g, respectively. The cut surface of both revealed a solid tumor with a variegated appearance of dark brown and yellowish areas [Figure 2]b. Microscopy showed a characteristic admixture of mature adipocytes and hematopoietic elements [Figure 3]a. A thin rim of normal adrenal parenchyma with capsule was also identified at the periphery [Figure 3]b, thus confirming the diagnosis of adrenal myelolipoma. Patients' postoperative course was totally uneventful.
Figure 2: (a) Large, round, 11 × 9× 4.5 cm encapsulated mass with smooth external surface. (b) Cut surface showing variegated appearance

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Figure 3: (a) Microscopic appearance showing typical histological features of myelolipoma comprising varying proportions of adipose tissue admixed with areas of hematopoietic tissue (H and E stain, ×40). (b) A thin rim of normal adrenal parenchyma with capsule at the periphery (H and E stain, ×10)

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  Discussion Top


Myelolipoma of the adrenal gland is a rare, benign, and biochemically inactive tumor comprising variable proportions of mature fat and hematopoietic elements. Their diagnosis is usually based on autopsy or imaging modalities which are performed for other reasons that are unrelated to adrenal diseases. The incidence ranges from 0.08% to 0.4%.[1],[4],[5] However, their prevalence appears to be increasing up to 15%, due to the recent advances in noninvasive and enhanced imaging techniques.[6] These lesions are mostly seen in the fifth to seventh decades and are usually unilateral and asymptomatic.[6],[7] However, few bilateral tumors have also been described. Myelolipomas are often smaller than 4 cm in diameter, but can reach variable sizes. The largest adrenal myelolipoma reported in the literature weighed 6 kg and measured 31 × 24.5 × 11.5 cm. These lesions generally do not recur after surgical resection.[3],[8] Adrenal gland is predominantly involved, but extra-adrenal presentations have also been reported in presacral area, stomach, liver, lymph nodes, mediastinum, and cranium.[9],[10] Approximately 36 extraadrenal myelolipomas have been described in English literature.[11] Their histogenesis is still uncertain, but different theories have been proposed, such as the development from stem cell rests, embolism of bone marrow cells, and extramedullary hematopoiesis. The most widely accepted theory is that by Meaglia and Schmidt, in 1992, which affirms that myelolipomas arise due to metaplasia of reticuloendothelial cells of blood capillaries in the adrenal gland in response to stimuli, such as chronic stress, infection, necrosis, or inflammation.[1],[10] Other contemporary authors have speculated about a stressful lifestyle and an unbalanced diet as factors that may be involved in the pathogenesis of this tumor.[3] Frequent association with obesity, type 2 diabetes mellitus, and arterial hypertension was observed.[4],[10] Most myelolipomas are asymptomatic but when the tumors grow large, they may cause compressive symptoms, tumor necrosis, or hemorrhage and present with abdominal and flank pain, palpable mass, or hematuria. Though usually nonfunctional, 10% are associated with endocrine conditions such as Conn's syndrome, Cushing's disease, and diabetes. There is no potential for malignancy.[4],[9]

CT is the preferred primary modality for evaluation which in most cases is done for some other reason. A majority of adrenal myelolipomas are composed of fat tissue, which has a negative HU value. The CT values are usually higher than those of retroperitoneal fat (typically measuring less than –20 HU) owing to the associated hematopoietic tissue component.[2],[9] If adrenal myelolipoma becomes larger, the differential diagnosis should include lipoma and liposarcoma.[1],[5],[9] The possibility could be low because these tumors rarely occur in adrenal gland, but sometimes percutaneous biopsy may be necessary to confirm the diagnosis.[9] The macroscopic analysis shows adipose yellow tissue with rare areas of hemorrhage and residual adrenal tissue. Myelolipomas are generally surrounded by a fine fibrous capsule and displace adjacent structures.[10] The microscopic examination reveals mature adipose tissue along with islands of elements of the three hematopoietic lineages with no maturation abnormalities.

In our cases, the macroscopic and microscopic findings were characteristic of myelolipoma. Lipoblasts, atypical adipocytes, mitotic activity, cellular pleomorphism, and necrosis were not noted. The residual adrenal tissue at the periphery of the lesion was composed of typical and uniform adrenal cortical cells.

Management of adrenal myelolipoma should be considered on individual basis. Small lesions, which are asymptomatic and less than 5 cm, should be monitored for 1–2 years with imaging controls.[1] Symptomatic tumors or myelolipomas larger than 5 cm should be surgically excised, so as to prevent an emergency because of spontaneous rupture and hemorrhage of the mass presented with life-threatening cardiovascular shock.[4],[10]

In cases such as ours, extraperitoneal approach is preferable than midline incision as it leads to quicker recovery of the patient and lesser postoperative complications.


  Conclusion Top


Although mostly discovered as an “incidentaloma,” the diagnosis of adrenal myelolipoma requires thorough diagnostic study. Imaging techniques such as USG and CT scans and biochemical studies are useful for deciding the best treatment depending on the size of the mass and hormone production. Surgical resection is advocated through extraperitoneal approach as it minimizes postoperative complications and leads to quicker recovery.

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

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Nabi J, Rafiq D, Authoy FN, Sofi GN. Incidental detection of adrenal myelolipoma: A case report and review of literature. Case Rep Urol 2013:789481.  Back to cited text no. 1
    
2.
Daneshmand S, Quek ML. Adrenal myelolipoma: diagnosis and management. Urol J 2006;3:71-4.  Back to cited text no. 2
    
3.
Brogna A, Scalisi G, Ferrara R, Bucceri AM. Giant secreting adrenal myelolipoma in a man: A case report. J Med Case Rep 2011;5:298.  Back to cited text no. 3
    
4.
Pamathy G, Jayarajah U, Gooneratne USP, Sivaganesh S. Incidental diagnosis of an adrenal myelolipoma: Case report. Sri Lanka J Surg 2017;35:35-6.  Back to cited text no. 4
    
5.
Singh H, Kundal R, Garg P, Kumar N. Incidental detection of adrenal myelolipoma: A rare case report. Research and reviews. J Med Health Sci 2015:4;84-6.  Back to cited text no. 5
    
6.
D'Addosio R, Rojas J, Bermúdez V, Ledesma F, Hoedebecke K. Case report: An incidentaloma that catches your eye – Adrenal myelolipoma F1000Res. 2017;6:1140.  Back to cited text no. 6
    
7.
Asil K, Ersavas M, Aksoy Y. Multicentric adrenal myelolipomas: Case report. J Med Cases 2015:6;91-4.  Back to cited text no. 7
    
8.
Zaheri S, Rashidi I, Malamiri MD, Jazayeri SN, Allahdin A. Adrenal myelolipoma: A case report. J Case Rep Images Pathol 2016;2:1-5.  Back to cited text no. 8
    
9.
Lin PC, Yang FS. Bilateral giant adrenal myelolipomas: A case report and literature review. Chin J Radiol 2008;33:61-4.  Back to cited text no. 9
    
10.
Gerson G, Beco MPFG, Hirth CG, Cunha MPSS, Lima FEMM, Parente FVC, et al. Giant retroperitoneal myelolipoma: Case report and literature review. J Bras Patol Med Lab 2015;51:48-51.  Back to cited text no. 10
    
11.
Kilinc N. Extra-adrenal myelolipoma: A case report and review of the literature. Pak J Med Sci 2007;23:779-8.  Back to cited text no. 11
    


    Figures

  [Figure 1], [Figure 2], [Figure 3]



 

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