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A huge left buttock mass in an old female
⁎Corresponding author: Abdoulkader Farida. farida.abdoulkader@gmail.com
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Received: ,
Accepted: ,
This article was originally published by Reed Elsevier India Pvt. Ltd. and was migrated to Scientific Scholar after the change of Publisher.
Abstract
Abstract
Myxofibrosarcoma also known as myxoid malignant fibrous histiocytoma is a rare soft tissue sarcoma that has a predilection for the elderly (beyond the 6th decade)
We report a case of a 64 years old patient that presented gradual appearance of huge tumor on her left buttock. Radiologic examination (MRI) concluded to MFS. There was no evidence of systemic involvement. The patient was directed in an oncology center, where the diagnostis of MFS was confirmed through surgical biopsy.
MFS is one of the most frequent sarcoma of soft tissue that occurs in elderly patients. This is an infiltrant tumor that is extending through muscular fascia. MRI is the gold standard in characterisation; it makes the positive diagnosis of MFS thanks to the myxoid signal, triple signal and the tail sign that is corresponding to the extension of the tumor into the muscular fascia and peri nervous spaces.
Cross-sectionnal imaging in particular MRI plays a key role in the positive diagnosis of soft tissue tumors. It makes possible to approach with great precision the exact nature of the tumor thanks to specific radiological semiology without however claiming to replace histology.
Keywords
Myxofibrosarcoma
Gluteal soft tissue
MRI
Tail sign
1 INTRODUCTION
MFS is a rare soft tissue sarcoma. This malignant tumor of connective sheats occurs preferentially in elderly people. It presents a high rate of recurrence bringing into play local and general prognosis. Even if a complete macroscopic resection is made, there is a microscopic contamination explaining the high rate of local recurrence.
2 Observation
This is a 64 years old female patient without any past history, coming in the clinic for a tenderness of the left buttock since 3 months evolving in a context of apyrexia and preservation of general condition. Clinical examination reveals a hard, firm mass on the left buttock, fixed in relation to the deep and superficial planes, with no change in the color of the adjacent skin. Ultrasound performed revealed a heterogeneous echogenic tissue mass that was difficult to characterize; cross-sectional imaging was recommended.
A CT scan performed in the following days revealed a deep, hypodense tumor embedded in the left gluteus maximus muscle, discreetly enhanced at the periphery, with contrast enhancement of the internal septa within it, suggesting an intramuscular myxoma; this mass measured nearly 15 cm in long axis[Fig. 1].
We completed it by MRI that confirmed the myxoid signal of the tumor (mild signal T1, high signal T2 and heterogeneous signal STIR with heterogeneous enhancement after Gadolinium injection). We could notice a significant peri-tumor edema in STIR hypersignal [Figs. 2–5].
Another particularity of this mass was the presence of extensions along the fascia with the sign of dural tail. It was therefore concluded to be a gluteal myxofibrosarcoma. The patient went to a hospital specializing in the treatment of sarcomas; a surgical biopsy was performed which confirmed the diagnosis.
She, then, benefited from several radiotherapy sessions followed by surgery with one-piece tumor resection.
The evolution was marked by the appearance of respiratory distress which prompted the performance of a chest CT scan, revealing a right pleural tissue process of myxoid density, compressing the tracheobronchial axis and the vessels of the mediastinum [Fig. 6].
Chemotherapy was undertaken for tumor cytoreduction in order to relieve compression on the SVC, without success; the patient died two months later.
3 Discussion
3.1 Epidemiology
Our observation highlights the major place of medical imaging in the positive diagnosis of some malignant tumor thanks to good tumor characterization which is intended to be as close as possible to histology in the particular context of developing countries.
To our knowledge, this extremely rare malignant tumor has not been reported in Djibouti.
MFS is one of the most common soft tissue sarcomas in the elderly; there is no predilection for sex..1 The usual locations in order of frequency are the lower limbs, followed by the pelvic, the scapular region and finally the trunk.1
3.2 Clinically
Usual clinical presentation is uni or multilocular infiltrating tumor of soft tissue which often extends along the fascia when it is superficial; the deep form is most often intermuscular rather than intramuscular.
3.3 Radiologic features
It presents particular characteristics in imaging.
Ultrasound is not effective for positive diagnosis. It presents as a heterogeneous non-lipomatous echogenic infiltrative area, moderately vascularized on Doppler and difficult to characterize.
CT scan, for its part, reveals a hypodense infiltrating mass of thick fluid density, moderately enhanced after injection. It makes it possible to guide the exact location of the mass and to specify the superficial or deep character depending on the situation to the fascia.
MRI is the gold standard in tissue characterization; it allows a positive diagnosis of this infiltrating tumor thanks to its own and widely documented radiological semiology.
Therefore, the MFS presents on MRI a myxoid signal which appears in hypo or iso T1 signal and pseudo-fluid hyper T2 signal with heterogeneous enhancement. Another particularity of MFS is the triple T2 signal2 corresponding to the association of myxoid signal, necrosis and blood which is a sensitive but non-specific sign. This triple signal is also found in other tumors such as synovialosarcoma, fibrosarcoma, and extra skeletal myxoid chondrosarcoma, to name but a few.2
The extensions along the fascia, intermuscular spaces or vascular-nervous pedicles are highlighted on the T1FS sequence after gadolinium injection producing the classic “tail sign”.1,2This sign is highly predictive of myxofibrosarcoma with a high sensitivity = 64–77% and specificity = 79–90%.2
This radiological sign is also predictive of a poor response to surgical treatment with poorer survival without local recurrence.2 Radiologists must be attentive to these MRI signs and inform the surgeon preoperatively in order to obtain a sufficient surgical margin and thus minimize the risk of local tumor recurrence.
3.4 Histopathologic features
From a histological point of view, we often find spindle and pleomorphic cells of variable cell density, a more or less significant myxoid component, depending on the grade, as well as elongated, arcuate, thin-walled vessels, surrounded by a condensation of tumor and/or lymphoplasmacytic cells. There is no recurrent genetic anomaly identified to date.3
Several histological grading systems exist. In Europe, the most widely used grading system is the FNCLCC (National Federation of Cancer Centers) which takes into account cellular differentiation, the proportion of tumor necrosis and the mitotic index. We thus distinguish 3 grades of increasing severity, the tumors being classified as low grade, intermediate grade and high grade.3,4
3.5 Therapeutic and prognosis
Histological grade remains the most important prognostic factor, particularly regarding to metastatic risk. It is also involved in indications for adjuvant chemotherapy. Sarcoma grade 1 almost never metastasize, their treatment is local (surgery often followed by radiotherapy in the event of insufficient excision margins). Adjuvant chemotherapy is generally reserved for grade 3 sarcomas, with a high metastatic risk.4,5
The prognosis is burdened by a significant risk of local recurrence estimated at nearly 50–60% of cases with greater histological aggressiveness.
Metastatic locations are most often in the lung, pleura and lymph nodes.4
The 5-year survival is estimated at 60–70%.5
4 Conclusion
Considering our local context where sophisticated histopathological are seriously lacking, making the diagnosis of this rare form of soft tissue sarcoma on the basis of imaging is a challenge.It is therefore the responsibility of the radiologist not to ignore, as far as possible, this tumor of undetermined aggressiveness in order to refer the patient to a specialized center as quickly as possible.
Ethical approval
The authors declare that the conduct of the research described in this article is in accordance with the Declaration of Helsinki of the World Medical Association revised in 2013 concerning experiments on patients or subjects, as well as with European directive 2010/63/EU concerning experiments animals.
Funding statement
WE HAVE NOT RECEIVED ANY FUNDING FOR THIS MANUSCRIPT.
Patients consent
Unfortunely, the patient passed out but we asked the family's consent and they signed.
Conflict Of Interest
THERE IS NO CONFLICT OF INTEREST.
CRediT authorship contribution statement
Abdoulkader Farida: Investigation, Writing – review & editing. Cespedes Yudy: revision. Said Elias: revision.
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