Myofibrosarcoma of the Adrenal Gland
S.A. MCLAUGHLIN, M.D.,* T.M. SCHMITT, M.D.,* K.L. HUGUET, M.D.,* D.M. MENKE, M.D.,+ J.H. NGUYEN, M.D .* From the Departments of *General Surgery and tPathology, Mayo Clinic Jacksonville, Jacksonville, Florida
Adrenal masses have varying presentations. Most commonly, adrenal masses are discovered incidentally on CT or MRI during an evaluation for an unrelated complaint. Although the ma- jority of these are nonfunctional cortical adenomas, hormonally active tumors and adrenocortical carcinoma must also be considered in the differential diagnosis. Rarely, retroperitoneal tumors may mimic an adrenal mass. We report a case of a 49-year-old man with anemia and weight loss who was found to have a large retroperitoneal mass arising from the adrenal gland. Surgical treatment involved en bloc resection of the right kidney, adrenal gland, segments 7 and 8 of the liver, and a portion of the right hemidiaphragm. Final pathology revealed a low-grade myofibro- sarcoma. We believe that this is the first case report of a myofibrosarcoma of the adrenal gland. Myofibrosarcomas are rare malignant tumors composed of myofibroblasts that arise from the deep soft tissues. These tumors have a predilection for the head and neck, trunk, or extremities. Myofibrosarcomas can be differentiated from other sarcomas by immunohistochemical staining and pathologic features. We will briefly discuss the workup of an adrenal mass and focus on the diagnosis of myofibrosarcoma.
M YOFIBROSARCOMA, also known as myofibroblas- tic sarcoma, is a rare malignant tumor. It can be distinguished from other sarcomas by immunohisto- chemical staining and pathological features. Although many types of nonfunctioning adrenal tumors have been identified, this is the first reported case of a myo- fibrosarcoma arising from the adrenal gland. The pa- tient’s clinical course and diagnosis of myofibrosar- coma are reviewed.
Case Report
A 49-year-old male presented to our clinic for the evalu- ation of anemia and a 20-pound weight loss. He reported no previous illnesses or surgeries, and he took no medications. His exam was unremarkable. Prior workup revealed nega- tive laboratory studies, chest radiograph, upper endoscopy and colonoscopy, cystoscopy, and intravenous pyelogram. However, an abdominal CT scan revealed a large retroper- itoneal mass (Fig. 1). The mass appeared to arise from the right adrenal gland involving both the right kidney and the posterior segments of the right lobe of the liver. Although the patient denied any symptoms suggestive of a hormon- ally active adrenal tumor, serum cortisol and serum aldo- sterone levels and a 24-hour urine for metanephrines were
obtained. Hormonal evaluation proved the tumor was bio- chemically nonfunctional. In addition, carcinoembryonic antigen (CEA), cancer antigen 19-9 (CA 19-9), alpha (a)- fetoprotein (AFP), and prostate specific antigen (PSA) lev- els were within normal limits. Exploratory laparotomy was then planned to remove the tumor en bloc.
A bilateral subcostal incision was made with midline ex- tension to the xiphoid. A Cattel maneuver was performed. On inspection, the tumor was adherent anteriorly to hepatic segments 7 and 8, posteriorly to the diaphragm, and inferi- orly to the right kidney. Systematic dissection allowed re- moval of the tumor en bloc with the right kidney, retroper- itoneal fat, hepatic segments 7 and 8, and a portion of the diaphragm (Fig. 2). The tumor did not invade the inferior vena cava. Pathological examination of the specimen re- vealed a low-grade myofibroblastic sarcoma measuring 13 cm in diameter and obliterating the right adrenal gland. Using immunohistochemical staining, the tumor stained positive for vimentin and muscle specific actin (Fig. 3) and stained negative for desmin, smooth muscle actin, and S-100. The patient did well and was discharged on postop- erative day 5.
Discussion
Adrenal masses can present in a variety of different ways and are typically classified by the presence or absence of hormonal activity. Patients with hormon- ally active tumors often demonstrate systemic or bio- chemical abnormalities characteristic of the adrenal tumor. Clinical presentation will give valuable clues to the hormonal nature of the tumor, but biochemical confirmation is still required. This evaluation should consist of serum electrolytes, a low-dose dexametha- sone suppression test, plasma aldosterone levels, and a
Presented at the Annual Scientific Meeting and Postgraduate Course Program, Southeastern Surgical Congress, New Orleans, LA, February 11-15, 2005.
Address correspondence and reprint requests to Justin Nguyen, M.D., Mayo Clinic Jacksonville, 4500 San Pablo Road, Jackson- ville, FL 32224.
24-hour urine collection for catecholamines and cor- tisol. These results will help determine the presence of Cushing’s syndrome, Conn’s syndrome, or a pheo- chromocytoma. All hormonally active tumors must be resected.
Incidental adrenal masses or “incidentalomas” are found in approximately 2-9% of all abdominal CT scans.1 The differential diagnosis includes adrenocor- tical adenomas, metastatic cancer, adrenal carcinoma, pheochromocytoma, cyst, or myelolipoma. These
asymptomatic tumors should be screened for hormonal activity. This hormonal screening is especially impor- tant in patients who have a personal history of prior malignancy. Once pheochromocytoma is excluded, a fine-needle aspiration may be performed. Lenert et al. reported that 52 per cent of incidentalomas in patients with recently diagnosed extra-adrenal malignancy were metastatic lesions.2
Once the incidentaloma is classified as nonfunction- ing, resection is based on size. Adrenocortical carci- noma is found in 1 of every 4000 adrenal masses. The risk of malignancy increases with the size of the tu- mor. Approximately 90 per cent of reported adreno- cortical carcinomas are greater than 6 cm.3 Adreno- cortical carcinoma notoriously presents late with advanced stage and poor prognosis. Adrenocortical carcinoma was our initial concern for this patient.
Rarely, retroperitoneal tumors such as liposarcoma or leiomyosarcoma can masquerade as an adrenal mass. This phenomenon has not previously been re- ported for myofibrosarcomas. Myofibrosarcoma is a controversial neoplasm composed of cells with differ- entiation toward myofibroblasts.4 These tumors typi- cally present as painless enlarging masses and have been reported in children and adults from ages 9 to 85. Most recently, 47 cases of low-grade myofibrosar- coma have been reported.5 This review documents myofibrosarcomas arising in the extremities, trunk, chest wall, breast, long bones, or head and neck. Up to one third of all reported cases have a predilection for the soft tissues of the head and neck including the tongue, oral cavity, and the face.5 According to Fisher, only half of the 47 known cases of myofibrosarcoma have been confirmed by electron microscopy. Ideally, the diagnosis should be supported by electron micros- copy and a combination of immunohistochemical analysis.
| Vimentin | CD 34 | Muscle-Specific Actin | Smooth Muscle Actin | Desmin | S-100 | |
|---|---|---|---|---|---|---|
| Liposarcoma | + | − | − | − | − | + |
| Leimyosarcoma* | + | − | − | + | + | − |
| Fibrosarcoma | + | − | − | − | − | − |
| Angiosarcoma | + | + | − | − | − | − |
| Myofibrosarcoma | +/- | − | +/- | +/- | +/- | − |
* Leiomyosarcoma can be differentiated from myofibrosarcoma by staining positive for calponin and h-caldesmon.5
The two largest series of low-grade myofibrosarco- mas are reported by Mentzel et al. (18 patients) in 1998 and Montgomery et al. (15 patients) in 2001.4, 6 Each reviews both the clinical and pathologic features of myofibrosarcomas, focusing on the microscopic ap- pearance and the immunohistochemical analysis. Clinically, the tumors ranged in size from 1.4 to 17 cm. Histologically, the tumors displayed infiltrative patterns composed mainly of spindle-shaped cells ar- ranged in fascicles.6 Most tumors in the subcutaneous tissues extended along connective tissue lines while deeper tumors “infiltrated between muscle bundles or bony trabeculae.”4 In most cases, the cells exhibited mild nuclear atypia and mitotic rates between 1 to 6 mitoses per 10 high-powered fields.6
In both series, all tumors stained positively by im- munohistochemistry for at least one myogenic marker. Frequently, the tumor was positive for a combination of several markers. In the series by Mentzel et al., 12 cases stained positive for desmin and 11 were positive for smooth muscle actin (SMA). Six stained positively for muscle specific actin (MSA). Seven tumors were desmin positive/smooth muscle actin negative, and five cases were desmin negative/smooth muscle actin positive.6 In the series by Montgomery et al., 13 cases were positive for SMA, 11 cases were positive for MSA, and six cases were positive for desmin.4 S-100 was negative in all cases. Immunohistochemical stain- ing is especially important to differentiate myofibro- sarcomas from liposarcoma, leiomyosarcoma, and fi- brosarcomas. Immunohistochemical findings of retroperitoneal sarcomas are summarized in Table 1.
Based on the cases reported, surgical resection is the mainstay of therapy focusing on achieving negative
margins. Radiotherapy has been used for higher-grade lesions or for those that are incompletely resected with unproven benefits.4, 6 Follow-up was available for 11 of the patients in Mentzel’s series and for 13 cases in Montgomery’s study, both at a median of 29 to 30 months. Recurrence rates were 27 per cent and 30 per cent, respectively for low-grade myofibrosarcomas. Most were local recurrences, however pulmonary me- tastases were found in two patients. These findings support radical surgery when necessary to obtain long- term survival.
We report the first case of a myofibrosarcoma aris- ing from the adrenal gland. After standard evaluation for an adrenal mass, the patient underwent surgical resection. Histology and immunohistochemistry con- firmed the diagnosis of myofibrosarcoma of the adre- nal gland.
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