Sarcomas of Muscular Tissue

Cutaneous leiomyosarcoma (LMS) is a rare tumor that accounts for 7% of soft tissue sarcomas. It arises from the arrector pili muscle of hair follicles or muscles associated with sweat glands. Subcutaneous LMS develops from vascular smooth muscle. There are no known causative factors. A relationship with irradiation, trauma, and malignant transformation of pre-existing leiomyoma is anecdotal. Median age at presentation is 40-70 years. There is no gender or racial predominance. The most frequent location is the thigh (Fig. 36). The tumor presents as a slowly growing, solitary mass that is red or blue. Ulceration and pain are variable. Histological examination shows typical muscular spindle cells arranged in bundles (224). Mitotic figures and nuclear atypia are common. Blunt-edged, cigar-shaped -g nuclei are characteristic (Fig. 37). IHC staining is positive for desmin, actin and |

vimentin. The current recommendation is surgical excision with 2 cm margins. ยป

Recurrent rates are as high as 40-60% (225). Mohs' surgery offers better margin -c control and tissue preservation. Adjuvant radiation therapy is indicated for tumors with high-grade histological characteristics, larger than 5 cm, or recurrent. Chemotherapy has been used only in the context of clinical trials. Nodal disease is best | treated with a lymph node dissection. Metastases, although rare in cutaneous LMS, are treated with surgery in combination with chemotherapy. The response rate varies between 15 and 30%. @

Cutaneous rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children and adolescents. Purely cutaneous RMS is exceedingly rare. It arises from primitive undifferentiated mesenchymal tissue, not from mature skeletal muscle as the name may suggest. The only predisposing factors are genetic, with familial aggregation and association with neurofibromatosis and retinoblastoma. Mean age at presentation is 10 years and the tumor predominates in males (226). The lesion presents nonspecifically as a subcutaneous nodule that grows slowly. Head and neck lesions account for 70% of cases, with the remaining tumors affecting the trunk (20%) and extremities (10%). Histological examination shows ill-defined aggregates of poorly differentiated round or oval cells. Hyaline fibrous septa and giant cells are characteristic. IHC stains are positive for desmin, actin, myoglo-bin, vimentin, and myosin. RMS requires a multidisciplinary approach for treatment. The current recommendation is surgical excision in combination with radiation and multiagent chemotherapy. The overall 5 year survival is 63% (227). Prognosis for localized, fully resected disease is excellent, with an 80-85% 5 year sur- g vival rate. Survival is lower for patients with incompletely excised tumors (65%) or g metastatic disease (20%). Metastatic spread occurs to lung, bone marrow, and lymph nodes.

Sarcomas of Neural Tissue |

Malignant peripheral nerve sheath tumor (MPNST) is rare and accounts for 10% of o soft tissue sarcomas. Ionizing radiation is the only known causative factor, however, it is present in only a minority of patients. The tumor usually manifests as a sudden

Figure 37 Typical blunt-edged nuclei in neoplastic cells of leiomyosarcoma. Malignancy is suggested by prominent hyperchromatism, nuclear atypia and abnormal mitotic figures.

growth of a pre-existing neurofibroma in patients with neurofibromatosis (228). The neoplasia is commonly associated with a nerve plexus and many patients have evidence of neuropathy or pain. Histological examination demonstrates spindle cells arranged in interlacing fascicles. Nuclear atypia and hyperchromasia are present. IHC stains are positive for S-100, vimentin, myelin basic protein, and neuron-specific enolase. Currently available therapy is disappointing. Wide surgical excision results in recurrence rates higher than 50% (229). The tumor is not responsive to either chemotherapy or radiation. Metastases are documented in 50% of deep-seated lesions.

Malignant granular cell tumor (MGCT) is a rare tumor. Mean age at presentation is 48 years. Lesions tend to be large (4-10 cm), grow rapidly, and become ulcerated. The most frequent location is the tongue. Histological examination shows polygonal epithelioid cells with granular eosinophilic cytoplasm. A characteristic pseudoepitheliomatous hyperplasia of the overlying epidermis is frequent (230). These changes are similar to those of benign granular cell tumors, but there is more pleomorphism, hyperchromatism, spindle cells, and necrosis. IHC stains do not differentiate between benign and malignant tumors. There is positive staining for vimentin, S-100, neuron-specific enolase, and myelin basic protein. The treatment of choice is wide surgical excision with regional lymph node dissection (231). Adju- c vant radiation is provided for aggressive tumors, positive nodal disease, and palliation for metastatic lesions. The value of chemotherapy is controversial but doxorubicin may be useful. Most series report 65% mortality at 3 years. Poor prog- |

nostic signs include older age, female gender, midline location, larger size, and evi- o dence of necrosis. Metastases occur via lymphatics to regional nodes and via blood to lungs, liver, and bones.

How To Reduce Acne Scarring

How To Reduce Acne Scarring

Acne is a name that is famous in its own right, but for all of the wrong reasons. Most teenagers know, and dread, the very word, as it so prevalently wrecks havoc on their faces throughout their adolescent years.

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