Introduction
Sinus histiocytosis with massive lymphadenopathy (SHML) also known as
Rosai-Dorfman disease is a benign, self-limiting disease that commonly
involve lymph nodes.1-6 The disease was first
described by Rosai and Dorfman in 1969 7,8 and since
then, there has been some many more cases reported from the available
literatures.
In terms of age and sex predilection, RDD commonly affect children and
young adult in their second decades life and shows slight male
preponderance.9-12
RDD may show an extra nodal disease pattern (23%) particularly by
having predilection to the head and neck region (75% of cases)4,13,14 and involvement of ≥1 extra nodal site has
been identified in 43% of cases.13 The tendency of
RDD to have simultaneous involvement of nodal and extranodal sites
remains to be rare and its diagnosis may be
challenging.12
SHML being a newly recognized and distinct pseudolymphomatous benign
entity has distinctive microscopic features though its
histocytomorphology has been documented in relatively few
cases.15
SHML has several clinical features that include massive painless,
bilateral, cervical lymphadenopathy which may be accompanied by
leukocytosis, fever, elevated erythrocyte sedimentation rate (ESR), and
hypergammaglobulinemia.1,4-6,8,10,13,16
In extra nodal cases though rare, SHML shows a distinct predilection to
the head and neck region 4,14 and involved extra nodal
sites include the eyes and ocular adnexa, head and neck, upper
respiratory tract, skin, subcutaneous tissue, bone, skeletal muscle,
central nervous system, gastrointestinal tract, salivary glands,
genitourinary tract, thyroid, breast, liver, kidney, heart, uterine
cervix.1,4,5,14 Misdiagnosis sometimes may be
encountered in patients with massive lymphadenopathy since they may be
labeled to be having lymphomas or other neoplasms depending on the
affected anatomical sites such as involvement of the nose and paranasal
sinuses by sinus histiocytosis.10,12,17
To date, the implicated etiological agent for RDD remains to be unknown
though there are several postulated theories to explain its
aetiopathogenesis. An autoimmune phenomenon (in about 10-12% of
patients) has been reported to be one of the
aetiology.13 Some infectious agents have also been
postulated in causation such as Polyomavirus, Epstein-Barr virus,
Parvovirus B19, Herpes virus type 6 and 8. 10,13Similarly, some relationship with microorganisms such as Klebsiella,
Brucella and Cytomegalovirus has also been postulated in its causation10,12,13 though any attempt to isolate such organisms
consistently failed.13
Other postulated mechanisms in pathogenesis of RDD include immune
dysfunction or an aberrant exaggerated immune response to an infectious
agent or an antigen that can cause proliferation of histiocytes and
similarly, stimulation of monocytes/macrophage via macrophage
colony-stimulating factor has also been postulated in causation8,12,13 thus suggesting immune system dysregulation in
patients with RDD.
We report such a case of Rosai-Dorfman Disease diagnosed by FNAC and
excisional biopsy with emphasis on clue to histocytopathological
interpretation.