Tag Archives: tumor

Giant conventional schwannoma of the foot: A case report

by Low Chin Aun, MBBS; Agus Iwan Foead, MS Orthpdflrg

The Foot and Ankle Online Journal 7 (4): 3

Schwannomas, also known as neurilemmoma, are amongst the most common tumors arising from peripheral nerves. It usually presents as a solitary swelling and may occur anywhere in the body with a neural supply. However, its occurrence in the foot is rarely reported. We report a case of a sixty year old man with a large schwannoma of his right foot, who never sought treatment for 20 years since its first occurrence.

Key words: Schwannoma, neurilemmona, tumor, foot

ISSN 1941-6806
doi: 10.3827/faoj.2014.0704.0003

Address correspondence to: Low Chin Aun
Department of Orthopaedic Surgery, Hospital Tuanku Ampuan Najihah, Kuala Pilah, Malaysia.
robinlca@gmail.com


Schwannoma is the most common benign, neurogenic tumor arising from Schwann cells of nerve sheaths. It occurs most frequently in the head and neck region, especially involving cranial nerves and brachial plexus. It is seldom reported in the upper and lower limbs [1]. This tumor grows in variable size and usually present as a slow growing solitary tumor, rarely associated with pain and paraesthesia. Neurological symptoms often accompany larger swelling. Its occurrence in the foot is rarely reported. Schwannomas constituted 5% of all benign soft-tissue tumors, and only 9% of these schwannomas were found in the foot or ankle [2]. We report a case of a large cutaneous schwannoma of the foot and its management.

Case Report

A 60-year-old man presented to our orthopaedic outpatient clinic with complaints of a solitary swelling over the lateral aspect of his right forefoot. He claimed the swelling has been gradually increasing in size for the past twenty years and was associated with intermittent pain and paraesthesia at his right foot. The swelling prohibited him from wearing his footwear due to its size. Patient has tried traditional treatment with massage and ointments but had no improvement. His past medical history was unremarkable and there was no family history suggestive of neurofibromatosis.

Physical examination revealed a 10cm x 10cm x 8cm tumor over the lateral aspect of his right foot (Figure 1). Its consistency was firm, and it was attached to the underlying tissue. On percussion, it produces an electric shock similar to Tinel’s sign. However, there was no tenderness, erythematous, warmth or ulceration of the skin over the tumor. Neurovascular status of the right foot was normal. Systemic review was unremarkable. Plain radiograph of the right foot did not show any bony involvement (Figure 2).

 fig1

Figure 1 Swelling on the lateral aspect of patient’s foot.

fig2

Figure 2 X-rays revealing a tumor on the lateral aspect of patient’s right foot.

At surgical excision, the capsule was found at the deeper plane. There was no attachment of the tumor with adjacent soft tissue which permitted easy in toto removal. The wound was then closed with split skin graft harvested from his left thigh. The patient did not experience any complication postoperatively. The tumor was preserved in formalin solution and sent to the pathology lab. One month later he was reviewed again in the clinic. There were no evidence of recurrence and his wound had healed well with good uptake of the skin graft (Figure 3). Histopathological examination revealed a conventional right foot schwannoma with cystic degeneration.

fig3

Figure 3 Well healed wound post-removal of schwannoma.

Discussion

Schwannoma of the foot is interesting due to its rarity. Its diagnosis and treatment should be differentiated with neurofibroma or malignant peripheral nerve sheath tumor (MPNST). Schwannoma is embryologically derived from neuroectodermal Schwann cell which forms the myelin sheath that facilitates transmission of nerve impulses [3]. This well encapsulated tumor is usually benign in nature and malignant transformation is rarely reported [4]. Multiple schwannomas have been reported to have autosomal dominant inheritance. These tumors have also been associated with von Recklinghausen’s disease in which there is somatic mutation of NF2 gene. It appears that it has no geographical and race predilection. The average age of its presentation is 20 – 50 years with a mean age of 46 [2].

Benign peripheral nerve sheath tumors are divided into two major groups; Schwannoma and neurofibroma. Differentiation of schwannoma from neurofibroma is of importance because schwannoma can easily be shelled out without injuring the nerve contiguity. In neurofibroma, the nerve is incorporated into the mass. Surgery of neurofibroma might need to resect the nerve, and subsequent nerve grafting might be needed to restore function. Large schwannoma commonly undergo cystic degeneration. Few neurofibromas have cystic changes due to myxoid degeneration. There has been argument about the cystic degeneration between the two tumors. Most literature showed schwannoma has higher chance of cystic degeneration compared to neurofibroma. Histogenesis of schwannoma and neurofibroma has been argued for decades and is beyond the scope of the discussion. It suffices to say that solitary schwannoma is composed almost exclusively of cells with characteristics of differentiated Schwann cells. However neurofibroma shows the presence of three types of cells, i.e. Schwann-like cells, perineurial-like cells, and fibroblast-like cells. Histologically staining with S-100 shows that schwannoma has hypercellular area alternating with hypocellular area, which respectively are called Antoni A, and Antoni B areas. The hypercellular area is made up of spindle cells with tapered nuclei arranged in palisading pattern whereas the hypocellular area is composed of loose stroma [4].

Malignant peripheral nerve sheath tumor (MPNST) is a sarcoma which can originate from peripheral nerve or from the cell associated with the nerve sheath, such as Schwann cell, perineural cell, or fibroblast [5]. The term MPNST replaces previously used names including malignant schwannoma, neurofibrosarcoma and neurogenic sarcoma. Fifty percent of MPNST occurs in patient with NF1 gene. It typically occurs between the ages of 20 – 50. The clinical presentation is almost the same as schwannoma and neurofibroma except the rapidly enlarging mass within the time spectrum alerts the physician of the possibility of its malignant degeneration. Histological appearance shows dense cellular fascicles alternating with myxoid region. This swirling arrangement is also called marbleized pattern. The cells may be spindle, round or fusiform in shape. Nuclear palisading is very rare compare with schwannoma and occurs in only 10% of cases. Malignancy is suggested by invasion of the surrounding tissue, and vascular structures, nuclear pleomorphism, necrosis, and mitotic activity.

Conclusion

Schwannoma of the foot is a rare tumor which present as solitary swelling of the extremity. Clinicians should always consider schwannoma as a differential diagnosis during approach of mass in the upper or lower limbs. It is essential to differentiate schwannoma with neurofibroma, and also MPNST as each entity is differently managed clinically.

References

  1. Knight DMA, Birch R, Pringle J. Benign solitary schwannomas: a review of 234 cases. J Bone Joint Surg [Br] 2007;89-B:382-7. (PubMed)
  2. Kransdorf MJ. Benign soft-tissue tumors in a large referral population. ARJ Am J Roentgenol. 1995;164:395-402. (PubMed)
  3. Berlin SJ. Soft somatic tumors of the Foot: Diagnosis and surgical management. Futura Publishing Co, Mount Kisco, NY: 227, 1976.
  4. Harkin JC, Reed RJ. Tumors of the peripheral nervous system, fascicle 3, second series. Washington, DC: Armed Forces Institute of Pathology, 1969:60-64.
  5. Endo M,Yamamoto H, Harimaya K, Kohashi K, Ishii T, Setsu N et al. Conventional spindle cell-type malignant peripheral nerve sheath tumor arising in a sporadic schwannoma. Hum Pathol. 2013 Dec;44(12):2845-8. (PubMed)

Extra-abdominal desmoid tumor of foot: A case report

by Kolur Puttaswamy Raju MS1, Mohan Kumar Jagadeesan MS1, Madhusudan Gururajarao Mch2, Dashavar Sreekantaiah Gangadhara MD3.pdflrg

The Foot and Ankle Online Journal 7 (2): 1

Extra-abdominal desmoid tumor is a rare tumor and only a few cases occurring in the foot have been reported. They are benign but locally aggressive, and wide local surgical excision is the treatment of choice owing to the high rate of recurrence in the lower extremities. Invasiveness into the surrounding soft-tissue structures often makes wide excision difficult without compromise of function. A 20-year-old man presented with gradually increasing swelling in the plantar aspect of left foot. He had a mild, dull, aching pain in the foot with increasing swelling. Wide local excision was done and the tumor was found mainly in the subcutaneous tissue, which histopathologically proved to be an extra-abdominal desmoid tumor. This case had an abnormal radiological appearance of the metatarsals with thinned sclerotic cortices. The patient had no recurrence at two year follow-up.

Key words: Extra-abdominal desmoid, tumor, wide excision

ISSN 1941-6806
doi: 10.3827/faoj.2014.0702.0001

Address correspondence to: Dr KP Raju, BGS GIMS & BGS Global Hospital, Bangalore
Email : drrajukp72@gmail.com

1 Department of Orthopaedics, BGS Global Hospital, Bangalore, India
2 Department of Plastic Surgery, BGS Global Hospital, Bangalore, India
3 Department of Pathology, BGS Global Hospital, Bangalore, India


Desmoid tumors, also known as aggressive fibromatosis, are an extremely rare entity is a locally infiltrative fibroblastic tumor that arises from fascial planes of soft tissue but does not metastasize. It is known to invade muscle, subcutaneous tissue and neurovascular structures. However, bone involvement is very rare and there have been few reports of bone involvement [1]. Desmoid tumors originate most frequently from abdominal fascial or musculoaponeurotic structures, although they may appear at extra-abdominal sites. The most common extra-abdominal locations include shoulder, chest wall, back, thigh, and head/neck [2,3]. Extremity desmoid tumors are extremely rare.

Desmoid tumors are unpredictable. Some tumors grow at a rapid rate. This can cause concern for an underlying malignancy. Other tumors remain unchanged after diagnosis. There are even instances of spontaneous regression. This erratic behavior makes treatment challenging. Treatment options vary. How a desmoids tumor is treated can depend upon the location of the tumor, its characteristics, and patient preferences. Surgery to remove the tumor is the preferred treatment method. However, it can be difficult during surgery to determine the limits of the tumor’s reach. This is because desmoids are not well encapsulated and they can intertwine with other tissues. The tumor can return after surgery, with local rates of return ranging from 25% to 68%. Desmoid tumors are notorious for invading a limb’s vital nerves and blood vessels. This means that full removal of the tumor may impair function in the surrounding area. In cases like these, limited surgery combined with additional treatments, such as radiation or chemotherapy, may be successful.

1

Figure 1 Plain radiographs of foot.

2 3

Figure 2 MRI of foot.

4

Figure 3 Intraoperative appearance of mass.

5

Figure 4 Histopathologic slide.

Case Report

A 20-year-old male presented to us with a mass in the left foot of two years duration. It was initially small in size but slowly progressive and causing difficulty in walking. On examination he had a 4×5 cm swelling on the plantar aspect. Radiograph showed deformed second, third, and fourth metatarsals with sclerotic cortices (Figure 1).

MRI showed a soft tissue mass arising from the deep fascia and engulfing the metatarsals (Figure 2). He had undergone previous biopsies which were inconclusive. Excision of the mass was performed, which was extending from the plantar to dorsal aspect engulfing the metatarsals (Figure 3). The 2nd and 3rd metatarsals were also excised along with the mass. Histopathology confirmed the diagnosis of extra abdominal desmoid (Figure 4). There was infiltration of the bones.

Postoperatively the wound healed well. Two years follow up revealed no recurrence and patient was walking full weight bearing.

Discussion

The incidence of desmoid tumors has been reported as 2–4 cases per 1 million [2,3]. They are typically derived from the abdominal wall, the bowel and its mesentery, or in extra-abdominal sites such as chest wall, shoulder girdle, inguinal region, and neck. Extra-abdominal desmoid tumors, as seen in our patient, very rarely originate from the extremities. The histologic appearance of the tumor is usually consistent in various microscopic fields within a given case as well as from case to case. Desmoid tumors are described as dense, collagenous lesions with intertwining bundles of spindle cells without epithelial components. The tumor cells are uniform and lack mitotic activity. No necrosis or pleomorphism is present [4]. Grossly the tumor appears as a dense, hard, rubbery, grayish-white mass. It usually is a fixed tumor, and total resection often is impossible without compromising nearby structures, as encountered in our case. Radical resection is necessary for successful excision since desmoid tumors tend to recur locally. However, surgery, radiotherapy, or both are regarded as the treatments of choice for these lesions [5].

References

  1. Ackman JB, Whitman GJ, Chew FS. Aggressive fibromatosis. AJR Am J Roentgenol. 1994;163 (3): 544. – Pubmed
  2. MacFarlane J. Clinical Reports of Surgical Practice of Glasgow Royal Infirmary. Glasgow, Scotland, 1832.
  3. Brenner P, Rammelt S. Abdominal wall and foot reconstruction after extensive desmoid tumor resection with free tissue transfer. Langenbecks Arch Surg. 2002;386 (8): 592-7.  – Pubmed
  4.  Lopez R, Kemalyan N, Moseley HS et-al. Problems in diagnosis and management of desmoid tumors. Am. J. Surg. 1990;159 (5): 450-3. – Pubmed
  5. Barbashina V, Karabakhtsian R, Aisner S et-al. Desmoplastic fibroma of the rib. Arch. Pathol. Lab. Med. 2002;126 (6): 721-2. – Pubmed

Additional Reading

  1. Macgill AA, Milione VR, Sullivan LG. Extra-abdominal desmoid fibromatosis in the foot: a case study. J Am Podiatr Med Assoc. 101 (1): 70-4. – Pubmed