DISCUSSION
We report the unusual cases of two children with symptoms suggestive for acute myelopathy, who resulted both affected by Primary Intramedullary Spinal Cord Lymphoma (PISCL). Though considered rare spinal canal tumors, PISCL should always be included in the differential diagnosis of acute myelopathy, because any delay in diagnosis and treatment could significantly impact on the prognosis of this disease.
Among the oncological causes of compressive myelopathy in the pediatric population, non- Hodgkin lymphomas (LNH) are the main group. LNHs are represented by a heterogeneous group of malignant neoplasms of lymph node tissue derived from the progenitors or mature B lymphocyte cells or, with lower frequency, T lymphocyte cells. While in adult the predominant subtype is low-grade, clinically indolent, lymphomas in pediatric age are mainly high-grade and characterized by an aggressive behavior (1). Extra nodal location in LNH of the child-adolescent, which differs from that of the adult, is more frequent, with involvement of the mediastinum, abdomen, head-neck district, bone marrow or central nervous system (2). Symptoms often develop rapidly, over a period of 1-3 weeks (see Table 1 for signs and symptoms). The onset of lymphadenopathy, with lymph nodes increased in size and indolent, is common as well as compression symptoms on the surrounding structures.
Our two clinical cases emphasize how clinical presentation of LNH frequently constitutes a challenge for the pediatrician because of the variety of possible onset manifestations and the different types of lymphomas and areas involved. For example: a chronic, deep, dull abdominal pain, devoid of specificity and precise localization, can characterize the onset of a LNH with primitively medullary localization. The main cause of this clinical sign is the stimulation of the nerve endings present in the wall of the bowel by the neoplasia (see Table 2 for red flags of PISCL).
However, acute abdominal pain is frequently a diagnostic challenge in children due to the difficulty in correctly interpreting a nonspecific symptomatology. Acute paraplegia in children is also a rare clinical presentation of lymphoma, with signs and symptoms reflecting spinal cord dysfunction. The 4 main etiological groups (see Table 3) of motor paralysis and/or functional deficit of the lower limbs in pediatric age consist of:
  1. trauma (for example, from falls or road accidents);
  2. vascular pathologies, including epidural spinal hematoma, caused by the rupture of epidural veins in correspondence of a locus minoris resistentiae following a sudden increase in intrathoracic or intra-abdominal pressure, due to efforts (even when of low intensity such as cough or defecation);
  3. inflammatory diseases (including primary infections, abscesses, polyradiculoneuropathy and infection associated processes, such as transverse myelitis and encephalomyelitis);
  4. compressions (tumors, syringomyelia) (11-12).
According to an Australian case study, the most common cause of acute flaccid paralysis of the lower limbs (up to 47% of cases) is GBS (5).
Malignant compression of the spinal cord (MCSC), whether it is caused by a primary tumor localization or as the consequence of a metastasis, can be divided into two types, depending on location: extradural (the most frequent in adults, extending from the vertebral bodies or from structures external to the dura mater) and intramedullary (14). Despite their impact on morbidity and mortality, only a small amount of data on the incidence of the disease are available in the pediatric population. Acute spinal cord compression can occur in a not negligible percentage of children with cancer, often at the time of diagnosis (15). Tumors associated with medullary compression in childhood are shown on table 4.
In an italian case study in pediatric oncology, motor deficit was the onset symptom of MCSC in all patients, while pain was reported in 60% of cases and sphincter deficit in 43% (3). MRI is the diagnostic technique of choice in all cases when there is suspicion of medullary involvement (3). This exam should be carried out as soon as possible because the neurological prognosis is strongly related to the promptness of spinal cord decompression surgery (11). Complications of spinal cord compression, such as urinary dysfunction, fecal incontinence, spasticity, painful syndromes and psychological sequelae are complex problems for children and adolescents (13). According to the latest 2013 guidelines of the American Association of Neurological Surgeons and the Congress of Neurological Surgeons, the use of glucocorticoids in acute traumatic spinal cord injury is no longer recommended.
The American Academy of Emergency Medicine states that glucocorticoid treatment remains an acceptable option. Many experts affirm that there are compelling and undeniable data justifying the clinical use of glucocorticoids, particularly in patients with incomplete lesions. The molecule to be used should be methylprednisolone, administered intravenously. The therapeutic scheme is:
30 mg/kg in bolus in 15 minutes
After 45’, 5,4 mg/kg infused every hour for 23 hours. (18)
A bladder dysfunction can lead to difficulties in urination associated with changes in intravesical pressure, an increased risk of infection and kidney damage as well as a source of social distress. Urinary symptoms can be very variable, ranging from an increase in urinary frequency to a complete urinary retention. It is therefore mandatory to perform a proper neurological examination (complete with evaluation of sphincter function and reflexes), a mintional diary, to measure residual post-mintional volumes and to execute urodynamic studies. Similarly, the presence of neurogenic bowel can be a source of serious social distress and skin impairment. Laxatives or anti-diarrheal drugs with pelvic floor rehabilitation can improve sphincter control (14). On the other hand, several studies show how neurological recovery in childhood is better than in adulthood (6) thanks to the greater plasticity of the immature spinal cord (7-8). In a recent work, the presence of residual muscle activity in children, found in electromyography analysis of the motor sites located below the level of injury, documents the existence of a residual descending influence from the spinal motor circuits. This observation, independently of its immediate functional relevance, can represent an objective indicator of the potential recovery of both intentional and postural motor function (16). Physiotherapy, following damage to the spinal cord, is still one of the key processes in the rehabilitation of the patient (9-10). Age at the time of diagnosis, location and degree of spread of the spinal cord injury are the main prognostic factors for the recovery of gait. Children under 5 years of age, with incomplete injuries, located in thoracic or lumbar spine, have the best chance of functional recovery thanks to physiotherapy (17).