[Hepatic myelolipoma: A rare entity, case report and review of the literature]. / Myélolipome hépatique : une entité rare, à propos d'un cas et revue de la littérature.

Hepatic myelolipoma is a rare entity with only 17 cases described in the literature. A 73mm right liver mass was fortuitously discovered in a 55-year-old man. The biopsy showed normal hepatic tissue adjacent to a normal medular like hematopoïetic tissue, showing trilieage hematopoieses, including myeloid cells, erythroid cells and megakaryocytic cells. The diagnosis of hepatic myelolipoma was proposed. This benign tumor was initially described in adrenal gland, which is the most common topography. No malignancy or bleeding complication has been described in its hepatical location. The diagnosis is histological due to non-specific radiological presentation; it allows to avoid a surgical treatment in relation to its excellent prognosis. The etiology is not well established; but some hypotheses are discussed: adrenal or medullar heterotopia, bone marrow embolism, myeloïd metaplasia.

Increased expression of ACTH (MC2R) and androgen (AR) receptors in giant bilateral myelolipomas from patients with congenital adrenal hyperplasia.

BACKGROUND: Although chronic adrenocorticotropic hormone (ACTH) and androgen hyperstimulation are assumed to be involved in the pathogenesis of adrenal myelolipomas associated with poor-compliance patients with congenital adrenal hyperplasia (CAH), the expression of their receptors has not yet been demonstrated in these tumors so far. METHODS: We analyzed Melanocortin 2 receptor (MC2R), Androgen Receptor (AR), Leptin (LEP), and Steroidogenic factor 1 (SF1) expression using real-time qRT-PCR in two giant bilateral adrenal myelolipomas from two untreated simple virilizing CAH cases and in two sporadic adrenal myelolipomas. In addition, the X-chromosome inactivation pattern and CAG repeat numbers in AR exon 1 gene were evaluated in the 4 cases. RESULTS: The MC2R gene was overexpressed in myelolipomas from 3 out of 4 patients. AR overexpression was detected in 2 tumors: a giant bilateral myelolipoma in a CAH patient and a sporadic case. Simultaneous overexpression of AR and MC2R genes was found in two of the cases. Interestingly, the bilateral giant myelolipoma associated with CAH that had high androgen and ACTH levels but lacked MC2R and AR overexpression presented a significantly shorter AR allele compared with other tumors. In addition, X-chromosome inactivation pattern analysis showed a polyclonal origin in all tumors, suggesting a stimulatory effect as the trigger for tumor development. CONCLUSION: These findings are the first evidence for MC2R or AR overexpression in giant bilateral myelolipomas from poor-compliance CAH patients.

Giant adrenal myelolipoma: when trauma and oncology collide.

Three patients presented some decades after severe traumatic injury with atypical bowel symptoms which were caused by a giant myelolipoma of the adrenal gland. The aetiology of this rare, benign and generally asymptomatic tumour is virtually unknown at present and several hypotheses have been devised. This report describes a possible association between high-energy trauma and the development of giant myelolipomas, further contributing to the hypothesis that severe systemic stress could be an aetiological factor in the development of an adrenal myelolipoma.

Adrenal myelolipoma: a mingle of progenitor cells?

Adrenal myelolipoma (AML) is a rare benign tumour composed or mature haematopoietic tissue and fat. The tumour is functionally inert and is usually detected incidentally. Mainly introduced in case reports, the tumourigenesis of AML is poorly understood with 3 historical hypotheses seemingly unrelated to each other. Here we propose the tumourigenic pathway based on the novel findings on stem/progenitor cell and our preliminary data. We hypothesize the tumourigenesis as follows: the fat components are derived by the mesenchymal stem cells of stromal fat of adrenal cortex under certain stimuli. Mature adipocytes begin to accumulate and become inflammatory stimulating neighbouring adrenal cortex tissue to release possibly G-CSF to recruit circulating haematopoietic progenitors. During the tumour growth, haematopoietic cell in the central part acquire energy from burning the surrounding fat until they are fully differentiated and division stops. Lacking the ability to further grow, the central part undergoes necrosis and calcification whilst the peripheral part continues to slowly pile up newly derived adipocytes and haematopoietic progenitor cells. The necrosis or calcification of the tumour the inflammation persists and the tumour generates a self-growing signalling loop, entailing a continuous growth even without further stimuli. Our theory offers a logical explanation to the diverse phenomena identified on AML and unifies the historical theories. Future studies may focus on the stem/progenitor cell profiles of AML to confirm and supplement our hypothesis.

A unique case of synchronous functional adrenocortical adenoma and myelolipoma within the ectopic adrenal cortex in a child with Beckwith-Wiedemann syndrome.

We report a unique case of synchronous functional adrenocortical adenoma and an incidental myelolipoma within ectopic cortical adrenal tissue located in the renal hilum in a child with Beckwith-Wiedemann syndrome and review the association between adrenal gland disorders and myelolipomas. To the best of our knowledge, this is the first documented case of a simultaneous occurrence of these three conditions. A 17-month-old child with Beckwith-Wiedemann syndrome was diagnosed with a left adrenal tumor during complementary radiologic studies. Biochemical investigation before surgery showed elevated blood levels of cortisol and dehydroepiandrosterone hormones. The patient underwent a left adrenalectomy with ipsilateral renal hilar and intercaval-aortic lymph node dissection. Pathology findings revealed a left adrenocortical adenoma and an incidental myelolipoma growing within ectopic cortical adrenal tissue in the renal hilum. The patient is doing well and does not have any current health issues. Patients with adrenal cortex disorders, such as hyperplasias and neoplasms, particularly when associated with hormonal imbalances, may have an increased risk of developing myelolipomas. Whether Beckwith-Wiedemann syndrome may, by itself, contribute to simultaneous occurrence of adrenocortical adenomas and myelolipomas remains to be clarified.

Adrenocortical neoplasms with myelolipomatous and lipomatous metaplasia: report of 3 cases.

OBJECTIVE: To present pathologic and radiographic features of 3 patients with adrenocortical neoplasms-2 with uncertain malignant potential and 1 adenoma with areas of myelolipomatous and lipomatous metaplasia. METHODS: We describe 3 patients who had adrenocortical neoplasms with foci of myelolipomatous and lipomatous metaplasia. For each patient, the clinical and pathologic data are reviewed. RESULTS: All 3 patients were women, with a mean age at presentation of 58 years. The lesion size averaged 6.8 cm (range, 3.9 to 11.0), and the mean gland weight was 128.8 g (range, 32.5 to 249). Two patients showed imaging findings compatible with adrenal myelolipoma. Pathologically, 2 of the lesions were classified as adrenocortical neoplasms of uncertain malignant potential, and 1 lesion was classified as an adrenocortical adenoma. All 3 lesions contained myelolipomatous foci throughout the neoplasm, and 2 of the tumors contained several pure lipomatous foci. CONCLUSION: Adrenocortical neoplasms, including those associated with an uncertain malignant potential, may be associated with areas of myelolipomatous and lipomatous metaplasia. Imaging studies may result in a false diagnosis of a benign adrenal myelolipoma and potential undertreatment in such patients.

Simultaneous adrenal and extra-adrenal myelolipoma - an uncommon incident: case report and review of the literature.

BACKGROUND: Extra-adrenal myelolipomas are rare benign tumours. Other soft tissue tumours such as well-differentiated liposarcomas appear morphological almost identical. Preoperative imaging and especially biopsy are important tools to diagnose these lesions. CASE PRESENTATION: We report a very seldom case of a simultaneous myelolipoma of the adrenal gland in association with an extra-adrenal myelolipoma in an 75-year-old man. With a review of the literature we describe and discuss the aetiology, differential diagnosis and treatment of patients with respect to adrenal and extra-adrenal lesions. CONCLUSION: The appearance of a simultaneous adrenal and extra-adrenal myelolipoma is a rare incident. We conclude that such lesions should be considered in the differential diagnosis of a fat-containing tumour in the retroperitoneal tissue/compartment.

[Extraadrenal perirenal myelolipoma: report of a case and review of the literature]. / Mielolipoma extraadrenal perirenal: aportación de un caso y revisión de la literatura.

Extra-adrenal myelolipomas are rare bening tumours that are componed of mature fat cells and myeloid elements. These lesions are usually asyntomatic and often found incidentally on radiographic studies. We report a case of extra-adrenal perirenal myelolipoma.

[Hemorrhagic adrenocortical adenoma with myelolipoma: a case report].

We present a case of hemorrhagic adrenocortical adenoma with myelolipoma. A 66-year-old woman was admitted to our hospital for left retroperitoneal mass. Based on abdominal computed tomography, magnetic resonance imaging and blood tests, preoperative diagnosis was a sarcoma of renal capsule origin. En bloc resection of adrenal gland, tumor, and the kidney with lymph node dissection was performed. Histologically, the mass was diagnosed as hemorrhagic adrenocortical adenoma with myelolipomatous foci.

Mielolipoma retroperitoneal / Retroperitoneal myelolipomas

El retroperitoneo es el espacio que se encuentra delimitado: por detrás, por la columna lumbar y los músculos psoas ilíaco y el cuadrado lumbar; por delante, por el peritoneo parietal posterior; por arriba, el diafragma; por debajo, el piso pelviano. Los tumores retroperitoneales representan el 1,8 por ciento del total de los tumores abdominales en nuestro servicio. Los mielolipomas comprenden el 0,08-0,4 por ciento de los mismos, siendo ellos tumores benignos compuestos por tejido adiposo y hematopoyético (incluye colonias eritroides, mieloides y megacariocíticas. El objetivo de este trabajo es definir alternativas terapéuticas en tumor benigno retroperitoneal

Defective apoptosis as potential mechanism in the tumorogenesis of myelolipoma.

Apoptosis is considered an important mechanism of selective deletion that occurs during hematopoiesis. Myelolipoma is a rare benign tumor composed of adipose tissue and hematopoietic cells. The pathogenesis of this benign tumor is still unclear. Analysing the structural levels and apoptosis of normal human bone marrow (NHBM) and human myelolipoma (HM), the apoptotic events resulted abundantly present in NHBM compared to HM, which showed a small number of apoptotic cells. By contrast, Fas expression was strongly present both in NHBM and HM. These findings suggest that an altered function of Fas in myelolipoma is not able to trigger the apoptotic machinery. In conclusion, we hypothesize that drastic reduction of apoptosis in myelolipoma can be considered one of the growth regulatory mechanisms.

Giant adrenal myelolipoma.

Adrenal myelolipomas are nonfunctioning benign tumors composed of hematopoietic elements and mature adipose tissue. These tumors usually remain small and asymptomatic; occasionally, however, they reach massive proportions and become symptomatic. To date, only two giant adrenal myelolipomas (>4,000 g) have been described in the literature. We describe the diagnostic evaluation and the operative management of the third largest adrenal myelolipoma reported.