Magnetic resonance imaging and computed tomography features of alveolar soft-part sarcoma in the right deltoid muscle: A case report

Abstract

Abstract. Alveolar soft-part sarcoma (ASPS) is a rare, highly vascular malignant soft-tissue tumor that predominantly affects young adults. The tumor can occur in any bodily region, but is most frequently observed in the lower deep soft tissues of the extremities, and is rarely observed in the upper extremities. The present study reported a case of ASPS of the right deltoid muscle. The patient presented with a 3-year history of a mass on the right shoulder that exhibited rapid growth in the month prior to diagnosis. Computed tomography (CT) and magnetic resonance imaging (MRI) were performed. The lesion mainly demonstrated isointense or mildly hyperintense signals compared with the muscle on the T1-weighted images of the MRI, and heterogeneous high signal intensity on the T2-weighted images. CT enhancement showed a homogeneous enhanced mass. The tumor was resected and submitted for histopathological examination. The diagnosis was verified as ASPS by microscopic examination and immunohistochemical analysis. No distant metastases were noted. No evidence of local tumor recurrence was seen at 6 weeks following the wide surgical excision. The CT scan revealed no metastatic nodules in either lung during the follow-up. ASPS should be considered as a possible diagnosis when a slow-growing, large mass is detected in young adults in the soft tissue of the extremities, with high signal intensity and numerous signal voids on T1-weighted images (T1WI) and T2WI, and strong contrast-enhancement. IntroductionAlveolar soft-part sarcoma (ASPS) is an infrequently encountered type of soft-tissue sarcoma that usually develops in the soft tissues of the extremities. The tumor accounts for <1% of soft-tissue sarcomas and predominantly affects teenagers and young adults (1). ASPS has a high propensity for metastasis and the lungs are the most frequent site of metastasis by the hematogenous route. Although prolonged survival is possible even in patients with metastasis, the long-term disease specific mortality rate is high. The prognosis of ASPS is poor due to the high frequency of metastatic disease. A large study indicated that the median survival time was 3 years if metastatic disease was present at diagnosis and 11 years without metastatic disease at presentation (1,2). ASPS is a rare, aggressive malignancy of uncertain histological origin, with a predisposition towards vascular invasion and distant metastasis. ASPS is most commonly observed in the extremities (1), but most commonly in the lower rather than the upper limbs. A previous study reported that ASPS is most commonly identified in the lower extremities (44%) and is rarely seen in the upper extremities (2).Magnetic resonance imaging (MRI) is the favored imaging modality for evaluation of this lesion due to its excellent soft tissue contrast, multiplanar imaging capability and lack of radiation exposure. Computed tomography (CT) enhancement and CT angiography clearly showed rich blood vessels within and around the tumor. The present study reports a case of ASPS of the right d...

Alveolar soft part sarcoma occurring in the penis of a 3-year-old boy

“…[ 10 ] Otherwise, the tumor exhibited large vessels and demonstrated intense contrast enhancement on CT and MRI. [ 11 ] These imaging findings are in agreement with the extremely vascular nature of ASPS, which is well correlated with the hypervascularity found in pathological specimens. [ 3 , 12 ] In contrast to others who have reported flow void of ASPS on MRI, we found no evidence of flow void in our case.…”

Computed tomography, magnetic resonance imaging, and F-deoxyglucose positron emission computed tomography/computed tomography findings of alveolar soft part sarcoma with calcification in the thigh: A case report

“…ASPS is a distinct, malignant soft-tissue tumor characterized by a pseudoalveolar architecture associated with abundant sinusoidal vessels. Adolescents and young adults, aged 15–35 years with a male to female ratio of 1:2, are more likely to be affected[ 1 - 3 ]. ASPS often develops in the lower extremities for adults; however, the head and neck are more frequently involved in children[ 4 - 6 ].…”

“…Although some primary malignant tumors, including liposarcoma and soft-tissue tumors, have high FDG uptake, the characteristic signal intensity on MRI images or density on CT images may be useful in differentiation. Differentiating ASPS with calcification from synovial sarcoma on CT and PET/CT images is difficult, but synovial sarcoma often showed no signal voids on MRI[ 1 , 9 , 13 ]. Therefore, the combination of these three examinations can provide more clues for the differential diagnosis of ASPS.…”

“…Alveolar soft part sarcoma (ASPS) is an extremely rare malignant sarcoma, constituting less than 1% of all soft-tissue sarcomas[ 1 ]. ASPS was first described by Christopherson et al[ 2 ] in 1952, deriving its name from its histological appearance[ 1 - 3 ]. The most common locations of ASPS are the lower extremities, head, and neck[ 4 - 6 ].…”

Imaging Features of Alveolar Soft Part Sarcoma: Single Institution Experience and Literature Review

“…It accounts for less than 1% of all STSs, usually affecting the extremities of children and young adults [2]. It is a very aggressive tumor characterized by poor prognosis, as well as a scarce response to radiation therapy and cytotoxic chemotherapy [2][3][4]. Surgical resection is the standard treatment based on complete resection with wide margins.…”