"A 19-year-old white male presents to you with a few weeks history of a large mass in the upper inner aspect of his left thigh. No trauma history and no other symptoms. What would you do?"
In order to answer this question you have to have some idea of the possible pathologies, the route and sites of metastasis, the best treatment plan and the most important prognostic factors.
Soft tissue sarcomas (including peripheral nerve sheath tumors which are basically treated the same) have a peak incidence at age 49 years, 90% white, without many known risk factors, 10% after trauma, especially desmoid tumors. 10% of Von Recklinghausen patients develop neurofibrosarcoma. Following radiation, especially head and neck sarcomas, after radiation therapy by many years, mostly osteosarcomas, and sometimes following surgical lymphadenectomy or axillary radiation for breast CA or melanoma (Lymphangiosarcoma was reported to develop in ipsilateral upper extremity - Stewart-Treeves syndrome) and finally, some chemicals have been reported to cause hepatic angiosarcomas (mainly anabolic steroids).
Soft tissue sarcomas mainly originate from mesodermal tissues (1/2 in the extremities, 1/4 in the retroperitoneum and 1/4 in the trunk, head and neck), and spread mainly by blood, with the exception of:
Clear cell sarcoma (30% incidence of lymph node involvement).
Epithelioid sarcoma (about 15% incidence of lymph nodes involvement).
So the most common sites of mets is the lung (and the liver in retroperitoneal sarcoma).
The most common soft tissue tumors are:
MFH (Malignant Fibrous Histiocytoma) 40%
The important prognostic factors are:
1. Histological grade (the most important: cellularity, nuclear atypia, mitosis/50 HPF i.e., more than 5-6 mitotic counts in 50 HPF, is considered high grade).
2. Size, depth, and site (extremities better than retroperitoneum).
3. Margins of resection (related only to local recurrence and not to long-term survival).
4. Vascularity and necrosis of the tumor.
Staging of sarcomas is based mostly on grade, size, involvement of lymph nodes, bone, blood vessels, and of course, distant mets. Now after this brief review we can answer the question.
Take a brief history and do physical exam (ask for trauma history, radiation, cafe au lait spots, etc.), then examine the tumor, the lymph nodes, the lungs, etc. Then do an incisional biopsy through a small longitudinal incision (that will not compromise your resection in the future). FNA is not acceptable; core needle multiple biopsies is an acceptable alternative or an excisional biopsy of lesions less than 3 cm. If the diagnosis is sarcoma, ask for the tumor grade immediately.
In low grade tumor => get CXR and MRI of the tumor (check for mets and local
invasion of vessels, bones and nerves). In retroperitoneal sarcoma get CT scan or
MRI of abdomen and check for the invasion of the surrounding structure and vena
If the tumor is high grade => get CT scan of the chest and MRI to the tumor.
Then do a wide local resection with 1-2 cm margin whenever possible. Muscle group excision (compartment excision) offers no benefit in terms of the patient's survival. In the thigh, if the vessels are invaded, they can be resected with the tumor and reconstructed with vein grafts (this applies to the arteries which can be reconstructed with inverted Saphenous vein segment but cannot to be applied to terminal veins). Sensory nerves can be sacrificed; motor nerves should be spared whenever possible.
You should have a discussion with the patient about the surgery and his/her alternatives (because, if the bone or motor nerves are involved, adequate excision may mean amputation or at least a paralyzed leg, he/she should be informed that the adequacy of resection affects the local recurrence rate and should the tumor recur after inadequate resection, he/she will need an amputation).
After surgery, if the patient has high-grade sarcoma or a low-grade sarcoma which is bigger than 5cm give the patient post-op radiation (needs about 6,000 rads to be effective which is possible in the extremities and unfortunately not possible in the trunk or retroperitoneal sarcoma because of the visceral toxicity).
Brachytherapy ( interstitial perioperative radiation therapy ) may have some role in near sensitive areas but has proven unfortunately to offer no advantage to external radiation therapy.
Chemotherapy (mostly Adriamycin based) has given so far poor results in sarcomas with the exception probably of osteogenic sarcoma, rhabdomyosarcoma, and Ewing variant sarcoma plus local recurrences. 40% of the patients die of their systemic disease.
Pre-op radiation is an option that can be considered in some large tumors in sensitive areas and is now a trend.