Amputation neuromas after neck surgery
Published Web Locationhttps://doi.org/10.5070/D336f5q2rg
Amputation neuromas after neck surgery
From the Departments of Dermatology, and Dermatopathology1, Hospital Universitario San Cecilio, University of Granada, Spain. email@example.comHospital de Poniente2 Almería (Spain)
Cristina Serrano Falcón1, Maria del Mar Serrano Falcón2, Ricardo Ruiz Villaverde2, Juan Linares Solano2, Salvio Serrano Ortega1
Dermatology Online Journal 11 (2): 24
Traumatic or amputation neuromas are benign tumours formed by a proliferation of Schwann cells, axons and connective tissue elements. They are secondary to the partial or total section of a nerve pathway due to an accidental or surgical trauma. They can form at any site and affect any type of nerve. The presence of amputation neuromas is very frequent in major surgery but rare in simple excisions of skin tumours. We report two cases with neuroma localized in the neck, one after lymph node dissection for melanoma metastasis and the other after excision of a cutaneous melanoma with 3-cm margin on lateral neck. In both cases, the presence of the neuroma mandated a surgical excision to rule out a possible recurrence of melanoma.
Amputation neuromas are secondary to the disordered proliferation of nerves and connective tissue after total or partial section of a nerve during an accidental or surgical trauma in an attempt to reinnervate the area. They are diagnosed some years after the trauma, usually by chance, as a small tumour near the scar that is tender to palpation or spontaneously painful. We report two cases of neck localization, one diagnosed 10 years after a cervical lymph node dissection and the other 6 years after the excision of a superficial spreading melanoma (SSM) with a 3-cm margin down to the fascia. Both cases were chance findings during the follow-up of melanoma patients with suspected lymph node recurrence.
Case 1.—A 38-year-old man was referred to our department in January 1981 for a melanoma tumor in the retroauricular area (SSM, 3 mm, ulcerated) and two clinically suspicious submandibular adenopathies. After tumor excision and lymphnode dissection, two of 21 isolated lymph nodes isolated were positive. The patient then received adjuvant treatment with DTIC. Followup examinations were normal until July 1996, when he was referred for a nodule, mildly tender to palpation, localized below the vertical scar to the cervical dissection and on the vascular bundle. An ultrasound scan revealed the presence of a poorly defined hypoechogenic nodule (1-cm maximum diameter) with good conduction, consistent with an adenopathy. The excision biopsy of the nodule confirmed the diagnosis of amputation neuroma.
Case 2.—A 43-year-old woman was referred to our department in July 1995 after a biopsy was taken of a pigmented tumor with pathological diagnosis of an ulcerated 3-cm SSM (ClarkÕs level III) on the lateral neck. The tumor was excised with a 3-cm lateral margin, including the platysma-colli muscle in the resection. The pathological study of the operative specimen did not demonstrate presence of tumor, and the patient did not receive adjuvant therapy. The followup was normal until May 2003, when a nodule was found 1 cm below the scar that was tender to palpation and spontaneously painful. Excision biopsy of the nodule confirmed the diagnosis of amputation neuroma.
|Figure 1||Figure 2|
|Fig. 2. Cross linked nerve bundles of medium size (x10)|
|Fig. 2. A: Schwann cells. B: Perineural cells (x40)|
|Fig. 3. A: S-100 stain positive in Schwann cells. B: EMA stain positive in perineural cells|
The pathological study in these two cases was identical, with observation of crosslinked nerve bundles of medium size (Fig. 1). At higher magnification there were scant morphological changes and presence of S-100 positive Schwann cells (Figs. 2A and 3A) and EMA-positive perineural cells (Figs. 2B and 3B).
An amputation or traumatic neuroma represents an attempt by an accidentally or surgically injured nerve to regenerate. When a nerve is transected, distal axons suffer Wallerian degeneration attributed to the inflammatory response, whereas the axons and Schwann cells of the proximal stump proliferate. Under normal conditions, the two segments eventually meet and the distal stump recovers innervation. However, if there is tissue between them, e.g., scar tissue, or if the distal stump is lost, nerve proliferation continues from the proximal stump without finding its assembly point, producing a disorganized cell tangle composed of neural fibers and connective tissue that extends into the surrounding soft tissues until it forms an amputation neuroma . The first published studies were in war veterans who developed painful neuromas after the amputation of one or more limbs .
These lesions can be classified into two types: spindle neuromas, caused by chronic friction or irradiation of a non-dissected nerve; and terminal neuromas, secondary to nerve transection . They present clinically as nodules below the lines of incision, sensitive to touch and with associated dysesthetic sensations. They usually do not exceed 2-cm in diameter, are diagnosed between 1 and 10 years after surgery, and can be located in any organ. Although more frequent in peripheral sensory nerves, they can affect any motor or sensory nerve and even nerves of the autonomic nervous system. In fact, the formation of amputation neuromas in sympathetic branches is not rare when the cystic duct is dissected during cholecystectomy.
The neck is prone to the development of amputation neuromas. All of the cases reviewed in the literature refer to major surgery, such as selective neck dissection. The great auricular nerve (C2-C4), cervical cutaneous nerve branches (C2, C3), supraclavicular nerve (C3, C4), and superficial branches of the cervical plexus  are commonly damaged in cervical lymph node dissection. The excision of an amputation neuroma is justified when there is a suspicion of a recurrence tumor or a lymphnode metastasis at this level, when it becomes painful, or when the patient requests it. Imaging techniques may soon obviate the need for surgery to confirm the diagnosis, although a consensus on their use has yet to be reached .
Histologically, amputation neuromas are characterized by an irregular organization of nerve fibres immersed in scar tissue. There may be concentric condensations of fibrous tissue around individual fascicles, giving the appearance of multiple separate nerves. Perineural cells surround each fascicle, unlike in palisaded encapsulated neuromas, where only the peripheral capsule contains these cells. As in many tumors of neural origin, numerous mast cells are scattered throughout the tumor .
Amputation neuromas are an unusual complication in the followup of patients with cutaneous melanoma. Our cases required an excision biopsy to rule out possible tumor recurrence or metastatic disease at this level. The formation of an amputation neuroma is frequent after cervical lymphnode dissection, as in our first patient. However, we have not found prior published case of this complication after minor surgery, as in our second patient, who underwent excision of a tumor with a margin of 3-cm down to the fascia and direct closure of the defect. Although the diagnosis is simple, based on clinical findings and surgical history, histological confirmation is recommended because of the aggressiveness of cutaneous melanoma.
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