Four cases of tumors classified as neurogenic sarcomas or tumors of nerve trunks are presented to illustrate a study of these neoplasms. They are derived from the connective tissue of the peripheral nervous system,—i.e., the epineurium, perineurium, or endoneurium. The term "neurogenic" applied to these tumors is misleading, since, it implies an ectodermic origin which, by definition, is incompatible with sarcoma. Hence we prefer the more unwieldy term "fibrosarcoma of the nerve sheath", as expressing more accurately the pathological concept of these neoplasms.
Clinically these tumors are characterized by slow growth, often existing from childhood. They may remain symptomless for many years, and suddenly become painful following trauma of even slight degree. Usually increase in size accompanies the onset of pain. Often the pain follows the distribution of the involved or associated nerve, and in this event the symptom is a great aid in diagnosis. It may be piercing or burning in character, but never in our experience does it resemble the dull gnawing ache of the periosteal or osteosarcoma. These tumors may be superficial or deep. The latter are more liable to be multiple, but must be distinguished from the neurofibromatosis of von Recklinghausen.
These tumors are all potentially, if not actually, malignant. The apparent harmlessness of a very small skin growth, obviously superficial, too often invites minor consideration which results in the unpleasant sequence of recurrence, metatasis, death. While in its primary state the tumor is of low-grade malignancy, trauma may activate it to a remarkably high degree. That trauma should not be thoughtlessly inflicted by the surgeon without full appreciation of the danger involved.
Many of these growths, especially the deeper ones, are encapsulated. Although relative benignity is thus preserved, it is no guaranty against recurrence. Metastasis in these tumors has been reported, even when surgery has not been used.
Early and complete excision followed by properly conducted deep radiation is the treatment advocated at present. Such tumors are quite radioresistant, so that treatment must be prolonged. At the operation the tumor will seldom be found associated with a large nerve trunk. The smaller muscular or cutaneous branches are more frequently involved. When no nerve structure is defined in the gross specimen, one may still discover strands of fibers in microscopic study.
The small, superficial, harmless-appearing, cutaneous nodule must not be exempt from consideration. It may be of considerable malignancy. Multiplicity must always be borne in mind, and as much search made for nearby growths as is feasible.