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Corresponding author: Balaji K. Jaganathan, MBBS, Department of Hand and Reconstructive Surgery, Apollo Hospitals, 21 Greams Lane, Thousand Lights, Chennai 600006, Tamil Nadu, India.
Sinus histiocytosis with massive lymphadenopathy or Rosai-Dorfman disease is a rare but well-established entity, commonly affecting the lymph nodes of the head and neck. Extranodal presentation, affecting the central nervous system, eye orbit, kidneys, testis, bones, upper respiratory tract, lungs, thyroid, small intestine, and peritoneum, has been reported. We present a case of a rare presentation of Rosai-Dorfman disease affecting the brachial plexus.
Sinus histiocytosis with massive lymphadenopathy, also known as Rosai-Dorfman disease (RDD), is a rare, benign, non-Langerhan cell histiocytosis. Rosai-Dorfman disease was first recognized as a separate clinical entity with distinguishing histopathology by Rosai and Dorfman
in 1969. It commonly affects children and adolescents in their first or second decade of life. The commonly affected lymphadenopathy site is the neck, but it has also been described in the mediastinal, axillary, inguinal, and retroperitoneal lymph nodes. Extranodal involvement has also been reported, including involvement of the bone, joints, skin, adnexa, lungs, upper respiratory tract, kidney, peritoneum, central nervous system, thyroid, small intestine, and eyelid.
We report a case of RDD involving the brachial plexus.
Case Report
A 24-year-old male patient was referred to our department in January 2020 from the department of neurology with complaints of weakness of the right upper limb and the inability to hold objects with the right hand. This was associated with muscle atrophy of his right upper extremity and continuous, dull, aching pain in both upper limbs for the past 4 years. He also reported gradually increasing weakness of his left upper extremity and both lower limbs over the last 6 months. There was also a history of bladder involvement presenting as stress incontinence. His bowel function was normal. There was no history of loss of weight or appetite and no history of fever. He had no other comorbidities.
On physical examination, the patient was conscious, oriented, and afebrile, with normal higher mental functions and speech. Both pupils were equally reactive to light. Extraocular movements were full. There was no facial weakness. On examining muscle tone, hypotonia was found more distally than proximally in the right upper limb and was normal in both lower limbs. Muscle power according to the Medical Research Council grading showed that the left arm and forearm muscles were generally graded as 4 out of 5 and the right arm and forearm muscles were generally graded as 3 out of 5. The grip strength of the right hand was considered weak based on a subjective judgment of the examining physician. The power of the proximal and distal groups of muscles in both lower limbs was 4 out of 5 and 5 out of 5, respectively.
More specific grading of the strength of individual muscles was not available. Deep tendon reflexes were brisk in the right upper extremity and absent in the left upper extremity. Deep tendon reflexes were elevated in both lower extremities. The plantar reflex was extension on both sides. Neck movements were full and supple.
Investigations showed a hemoglobin level of 10.2 g/dL, packed cell volume of 32%, white blood cell count of 5,400 cells/mm3 (neutrophils 63%, lymphocytes 32%, eosinophils 2%, and monocytes 3%), platelet count of 423,000 cells/mm
, erythrocyte sedimentation rate of 90 mm/h, serum protein level of 9.9 g/dL, serum albumin level of 2.9 g/dL, serum globulin level of 7.0 g/dL, reversed albumin-to-globulin ratio, serum free lambda level of 33.68 mg/L, and serum free kappa level 22.16 mg/L, indicating a polyclonal increase in immunoglobulin levels. Serum electrophoresis showed an increase in beta-2 and gamma levels and normal limits of alpha-1, alpha-2, and beta-1 levels.
Electrodiagnostic studies showed normal distal and proximal latencies, amplitude, and conduction velocities in both tibial and peroneal nerves. The right median and ulnar compound motor action potentials were unrecordable. The left median and ulnar nerves showed prolonged latencies, with reduced compound motor action potentials and conduction velocities. The late response F-wave latencies were within normal limits in the lower limbs and unrecordable in the upper limbs. These results suggested a sensory motor neuropathy of the upper limbs. Magnetic resonance imaging of the cervical spine and brachial plexus showed bilateral and symmetrical uniform diffuse thickening of the cervical nerve roots and brachial plexus trunk (C5 to T1). The lesions showed mildly bright signal changes on T2 and short-TI inversion recovery sequences with restricted diffusion on diffusion-weighted imaging. There was a signal alteration in the marrow of the sternum, upper end of the left humerus, distal clavicle, and acromion. Bilateral axillary and supraclavicular nodes were enlarged. These findings were suggestive of a chronic, inflammatory demyelinating polyneuropathy or neurofibromatosis (Fig. 1).
Figure 1Magnetic resonance imaging of the brachial plexus in the cervical spine. A T2-weighted signal image shows uniform diffuse thickening of the nerve roots and trunk (the yellow arrows show the thickened roots).
Because the workup was inconclusive in arriving at a diagnosis, it was decided that a nerve biopsy would be performed. In this regard, the left upper extremity was chosen because although the right upper extremity was more affected than the left, it was decided that it was better to avoid the risk of any additional iatrogenic deficit to the right upper extremity. A single fascicle left ulnar nerve biopsy of the cubital tunnel was performed, which showed perineural fibrosis, with no significant inflammation or evidence of demyelination. This did not clarify the diagnosis, and so, it was decided that a second procedure would be performed to explore the left brachial plexus. Guided by the same reasoning as earlier, the choice to explore the left, rather than the right, brachial plexus was made. During the second procedure, the left brachial plexus was explored through a supraclavicular incision. All nerve roots from C5 to T1 were found to be thickened, enlarged, and friable (Fig. 2). The anterior division of C7 was biopsied. After the surgery, no new deficit in the left upper limb was observed.
The histopathological findings of the biopsy specimen showed extensively dilated sinusoids filled with histiocytes with emperipolesis and phagocytic lymphocytes, neutrophils adherent to histiocytes, reactive follicles, and plasmacytosis (Fig. 3). The findings were consistent with those of RDD of the C7 nerve root. The immunohistochemistry result was positive for cluster of differentiation (CD)3, CD20, CD68, and S100 and negative for CD1a and CD30, reinforcing the diagnosis of RDD.
Figure 3Histopathology of the nerve root shows the features of RDD (dilated sinusoids filled with histiocytes with emperipolesis and phagocytic lymphocytes, with a nerve bundle outside the capsule; H&E staining).
After establishing the diagnosis, further management was supervised by a neurologist using oral steroids. Clinical improvement was seen 6 months after the surgery, after which the patient was lost to follow-up.
Discussion
Rosai-Dorfman disease is a rare entity affecting the lymph nodes and extranodal tissues. Although a well-established entity, the initial diagnosis of the disease remains a challenge owing to the varied systemic presentations. Clinical features such as low-grade fever, normocytic normochromic anemia, elevated erythrocyte sedimentation rate, leukocytosis, and hyperglobulinemia, are all nonspecific findings.
The diagnosis of RDD is established by the presence of histological alterations in the biopsy of an affected lymph node. Distension of sinusoids, characterized by pale-staining histiocytes, intermixed with a variable number of mature plasma cells is the characteristic feature of RDD. Individual histiocytes contain 1 or more intact lymphocytes in the cytoplasm, where these lymphocytes continue to move freely via a process known as emperipolesis. Immunohistochemistry studies show the presence of S100 in most cases.
Even then, the histopathology of extranodal RDD is highly inconsistent. The magnetic resonance imaging-based finding of homogenous thickening of the entire brachial plexus is a nonspecific finding, also seen in conditions such as chronic inflammatory demyelinating polyneuropathy and neurofibromatosis.
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