Spinal extra-dural metastasis from Merkel cell carcinoma: a rare cause of paraplegia

Abstract

We report a rare case of Merkel cell carcinoma with extra-dural spinal metastasis causing paraplegia. There are only four reported cases in literature. A 57-year-old lady presented with a breast lump, multiple truncal skin swellings, low back pain and rapidly progressive paraplegia. MRI showed multiple epidural soft tissue masses causing neural compression. A biopsy from the truncal skin lesion was diagnosed as Merkel cell carcinoma (MCC). Posterior decompression and tumor debulking at all three sites of neural compression was performed. Histopathology of the epidural tumor was consistent with MCC and the diagnosis was confirmed by immuno-histochemistry staining for cytokeratin-20. She was started on chemotherapy and radiotherapy. One month after diagnosis she died due to extensive metastasis. The short term palliative response seen in our patient demonstrates the poor prognosis for patients with spinal metastasis.Keywords Merkel cell carcinoma Á Spinal metastasis Á Secondaries Á Paraplegia Case reportA 57-year-old diabetic lady presented with persistent low back pain and bilateral radiculopathy of 2 months duration followed by rapidly progressive weakness and numbness of the lower limbs. She also had loss of bowel and bladder control since 1 week. Multiple painless skin lumps over the chest and abdomen had appeared spontaneously a few months prior to presentation. There were no constitutional symptoms. General examination revealed multiple firm nontender shiny skin lumps approximately 3-4 cm in diameter on the anterior abdominal wall, chest and on the right breast. There were also firm and non-tender mobile lymph-nodes of 2-3-cm size in the right posterior triangle of the neck (Fig. 1a). There was no tenderness or pain on movements of the spine. She had a flaccid paraplegia, a left extensor plantar response and sensory hypoesthesia below the ninth thoracic dermatome bilaterally. The radiographs and CT scan done prior to admission were normal (Fig. 1b, c). An MRI showed epidural soft tissue masses causing neural compression at the eighth thoracic, fourth lumbar and first sacral levels. There were also with multiple soft tissue lesions in the paraspinal and retroperitoneal space--features suggestive of metastasis. There was no history to suggest immuno-compromised status and human immunodeficiency virus infection was eliminated by the appropriate laboratory tests.An FNAC of the lymph node, anterior abdominal wall mass and right breast was reported as a small cell tumor. An incisional biopsy from a skin lesion was reported as MCC. A laminectomy and tumor debulking at all three sites of compression was performed. Epidural tumor tissue sent for histopathology was reported as a high grade malignancy composed of epitheliod cells with scanty cytoplasm, markedly pleomorphic nulei having a ''salt and pepper'' chromatin (highly reminiscent of a neuro-endocrine origin). The tumor cells with numerous mitosis were predominantly disposed in a trabercular and cribriform pattern and also arranged around necrotic space...

Metastatic Merkel cell carcinoma of the spine

“…1 MCC presenting with neurological complications is rare; 2 with only four reports 1,3-5 with spinal metastasis, with only one patient having a marked neurological deficit that required surgical decompression. 6 In that report in 2008, 6 Vijay et al suggested that there had been four prior patients. However, our detailed review of those publications reveals that one 5 was a reflective letter by a primary author on a previously reported case.…”

“…This neurological presentation is not unlike the patient in Vijay et al's report. 6 However, that patient had multilevel compressive lesions without any bony destruction suggestive of instability. The rapid incomplete neurological deficit, with associated bowel and bladder incontinence, mandates an urgent decompression of the spinal cord.…”

“…Three of the four previously reported patients died early from extensive metastasis despite aggressive local treatment. 3,4,6 Two patients with metastatic Merkel cell tumor of the spine required surgery. The first report was of L5 radiculopathy in a 63-year-old male with a primary epigastric Merkel cell tumor.…”

“…One month after diagnosis she died due to extensive metastasis. 6 Herein we describe a patient with metastatic MCC of the spine presenting with progressive neurological deficit and incontinence. This neurological presentation is not unlike the patient in Vijay et al's report.…”

Thoracic Spinal Metastasis of Merkel Cell Carcinoma in an Immunocompromised Patient: Case Report

“…There are only five reports of spinal metastasis from MCC in the literature1,2,3,4,5; we report the sixth case.…”