Rosai-Dorfman disease (sinus histiocytosis with massive lymphadenopathy — SHML) is a rare benign histiocytic proliferative disorder. It characteristically presents with massive, painless, bilateral cervical lymphadenopathy. Most commonly seen in childhood and young adulthood (under 20 years), with slight male predominance and higher incidence in populations of African descent. Histopathologically, expanded sinuses containing histiocytes with emperipolesis (engulfment of lymphocytes within histiocyte cytoplasm) is pathognomonic. Approximately 40% of cases have concomitant extranodal involvement (skin, upper respiratory tract, bone, orbit, central nervous system). Most cases are self-limiting, though treatment may be required for vital organ involvement. On imaging, numerous enlarged, homogeneously enhancing lymph nodes in bilateral cervical regions are observed; necrosis is generally not expected.
Age Range
5-40
Peak Age
20
Gender
Male predominant
Prevalence
Rare
The exact etiology of Rosai-Dorfman disease remains unknown; however, immune dysregulation, viral triggers (HHV-6, EBV), and genetic predisposition (SLC29A3 mutations) have been proposed. The pathological process is characterized by excessive proliferation and activation of sinusoidal histiocytes. These histiocytes are S100-positive and demonstrate emperipolesis — intact lymphocytes, plasma cells, and erythrocytes are harbored within histiocyte cytoplasm without phagocytosis. Histiocyte accumulation leads to expansion of lymph node sinuses and massive lymphadenomegaly. On imaging, this massive histiocytic infiltration causes homogeneous enlargement of lymph nodes; necrosis and calcification are generally absent because the process is benign and does not cause vascular destruction. Homogeneous soft tissue density enhancement on CT results from the rich vascular stroma of histiocytes. T2 hyperintensity on MRI relates to the high cellular content and edema of histiocytes; diffusion restriction on DWI reflects the dense cellular infiltration.
The presence of massive, painless, homogeneously enhancing, non-necrotic multiple lymph nodes in bilateral cervical regions of a young patient (child or young adult) is highly characteristic of Rosai-Dorfman disease. This pattern differs from lymphoma which generally shows heterogeneous enhancement and possible necrosis, and from metastatic LAP which is usually unilateral and necrotic.
Numerous enlarged, oval-to-round lymph nodes are seen in bilateral cervical regions. Nodes appear homogeneously hypoechoic with generally uniform internal echo structure, and necrotic areas are not expected. Hilar echo is usually preserved or thinned due to compression. Nodes are generally not conglomerate and do not demonstrate coalescence. Sizes can be dramatic — short axis may reach 3-5 cm.
Report Sentence
Multiple enlarged lymph nodes (largest short axis ___mm) are noted in bilateral cervical regions, appearing homogeneously hypoechoic without necrosis, and sinus histiocytosis with massive lymphadenopathy (Rosai-Dorfman disease) should be considered in the differential.
On color Doppler ultrasonography, hilar vascular pattern is generally preserved in lymph nodes. Vascularity may be increased but distribution remains hilar type — peripheral or chaotic vascularity is not expected. This finding is important in distinguishing from the mixed/peripheral vascularity of lymphoma and peripheral vascularity of metastatic LAP. Prominent flow signals are seen in hilar vessels on power Doppler.
Report Sentence
Doppler ultrasonography demonstrates preserved hilar vascular pattern in enlarged lymph nodes without peripheral or chaotic vascularity; this finding favors benign histiocytic proliferation consistent with Rosai-Dorfman disease.
On contrast-enhanced CT, multiple enlarged lymph nodes in bilateral cervical regions demonstrate homogeneous enhancement. Nodes are well-defined and surrounding fat planes are preserved — perinodal infiltration is not expected. Enhancement degree is moderate to prominent. Necrosis, calcification, or extracapsular extension is generally absent. Concomitant enlargement may also be present in mediastinal, axillary, and inguinal lymph nodes, but cervical involvement predominates. Sizes can be striking — individual nodes may reach 5-6 cm.
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Contrast-enhanced CT demonstrates multiple enlarged (largest ___mm), well-defined, homogeneously enhancing lymph nodes without necrosis or calcification in bilateral cervical regions; findings are consistent with massive bilateral lymphadenopathy of Rosai-Dorfman disease.
On T2-weighted images, enlarged lymph nodes demonstrate homogeneous hyperintense signal. Signal intensity is markedly higher than muscle, lower than fat. Homogeneity reflects the orderly structure of histiocytic infiltration — heterogeneous signal or necrotic areas are not expected. Perinodal soft tissue edema is minimal. Bilateral symmetric involvement pattern is notable.
Report Sentence
On MRI T2-weighted sequences, bilateral cervical enlarged lymph nodes demonstrate homogeneous hyperintense signal without necrotic or heterogeneous areas.
On diffusion-weighted imaging (DWI), enlarged lymph nodes demonstrate significant diffusion restriction — hyperintense signal at high b-values (b=800-1000) with low signal on ADC maps. ADC values are generally in the range of 0.7-1.0 × 10⁻³ mm²/s. Diffusion restriction reflects dense histiocytic cellular infiltration. Similar degree of restriction is seen across all enlarged nodes — heterogeneous ADC values are not expected.
Report Sentence
On DWI, bilateral cervical enlarged lymph nodes demonstrate significant diffusion restriction (ADC: ___×10⁻³ mm²/s), consistent with dense cellular infiltration.
On FDG PET-CT, enlarged lymph nodes demonstrate moderate FDG uptake (SUVmax generally in the range of 3-8). Uptake is homogeneous and at similar levels across all involved nodes. SUVmax values tend to be lower compared to aggressive lymphoma. Extranodal involvement sites (if present) may also be FDG-avid. PET-CT is used for assessing disease extent and monitoring treatment response.
Report Sentence
FDG PET-CT demonstrates moderate homogeneous FDG uptake in bilateral cervical enlarged lymph nodes (SUVmax: ___); findings are consistent with Rosai-Dorfman disease and lower than the intense uptake expected for aggressive lymphoma.
Criteria
Bilateral cervical massive lymphadenopathy predominant, no or minimal extranodal involvement. Most common form (60%). Generally self-limiting.
Distinct Features
On imaging, only lymphadenopathy is observed without additional organ involvement. Bilateral symmetric enlarged nodes are the dominant finding on CT and MRI. Young age group (10-20 years) predominates.
Criteria
Extranodal organ involvement present with or without lymphadenopathy. Most common skin (10%), bone, upper respiratory tract, orbit, and CNS involvement. 40% of cases have simultaneous nodal+extranodal involvement.
Distinct Features
On imaging, additional organ lesions are observed alongside lymphadenopathy. CNS involvement shows dural-based enhancing mass (meningioma-like), orbital involvement shows retrobulbar soft tissue mass, bone involvement shows lytic lesions. May present in a wider age range.
Criteria
Only skin involvement present, no lymphadenopathy. Unlike nodal form, usually seen in older adults. Cutaneous lesions as papules, nodules, or plaques. S100+, CD68+ histiocytes with emperipolesis seen in dermal infiltration.
Distinct Features
No lymphadenopathy on imaging — diagnosis is made clinically and by biopsy. Subcutaneous nodular lesions may be seen on US. Prognosis is better than nodal form.
Distinguishing Feature
In NHL, enlarged nodes may show heterogeneous enhancement and necrosis; in Rosai-Dorfman enhancement is homogeneous and necrosis is not expected. NHL occurs in a wider age distribution and B symptoms (fever, night sweats, weight loss) may accompany.
Distinguishing Feature
In TB lymphadenitis, rim enhancement (central necrosis + peripheral enhancement) is characteristic; in Rosai-Dorfman there is no necrosis and enhancement is homogeneous. Calcification may be seen in TB and involvement is usually unilateral or asymmetric.
Distinguishing Feature
In Castleman disease (hyaline vascular type), hypervascular nodes show intense enhancement and usually solitary or localized clustering; in Rosai-Dorfman enhancement is more moderate and massive bilateral involvement is typical. Central calcification and feeding vessels may be seen in Castleman.
Distinguishing Feature
In Hodgkin lymphoma, FDG uptake is generally more intense (SUVmax >10) and mediastinal involvement is common; in Rosai-Dorfman FDG uptake is moderate (SUVmax 3-8) and cervical involvement predominates. Internodal coalescence (conglomerate mass) is more common in Hodgkin.
Distinguishing Feature
In Kikuchi disease, cervical LAP is usually unilateral and predominant in the posterior triangle, nodes are smaller (<3 cm) and may be painful; in Rosai-Dorfman LAP is bilateral, massive, and painless. Fever and leukopenia accompany Kikuchi, while these findings are not prominent in Rosai-Dorfman.
Urgency
routineManagement
surveillanceBiopsy
NeededFollow-up
6-monthRosai-Dorfman disease is generally a self-limited condition and treatment is not required in most cases. Diagnosis is made histopathologically by excisional biopsy — demonstration of emperipolesis in S100+/CD68+ histiocytes is diagnostic. In cases of vital organ involvement (CNS, orbit with vision loss, airway obstruction) or symptomatic massive LAP, steroids, chemotherapy (cladribine, methotrexate), or radiotherapy may be administered. Prognosis is excellent in most patients with expected spontaneous remission. Follow-up is recommended to monitor for disease progression and development of extranodal involvement.
Rosai-Dorfman disease is generally self-limiting and does not require treatment. However, surgery, corticosteroids, or low-dose chemotherapy may be needed for vital structure compression or symptomatic extranodal involvement. Overall prognosis is excellent.