Table of Contents
Definition / general | Essential features | Terminology | ICD coding | Epidemiology | Sites | Pathophysiology | Etiology | Clinical features | Diagnosis | Laboratory | Radiology description | Radiology images | Prognostic factors | Case reports | Treatment | Clinical images | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Cytology description | Cytology images | Positive stains | Electron microscopy description | Molecular / cytogenetics description | Differential diagnosis | Additional references | Board review style question #1 | Board review style answer #1Cite this page: Balakrishna J, Sharabi A. Dermatopathic lymphadenitis. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/lymphnodesdermatopathiclymphadenitis.html. Accessed February 8th, 2023.
Definition / general
- Type of paracortical hyperplasia, commonly occurring in lymph nodes draining areas with chronic skin irritation
Essential features
- Paracortical expansion with nodular proliferation of interdigitating dendritic cells, Langerhans cells and histiocytes
- Most often pigment in the histiocytic cytoplasm, including melanin and rarely iron
Terminology
- Dermatopathic lymphadenitis (J Invest dermatol 1942;5:197)
- Lipomelanotic reticulosis (Ann Derm Syph 1937;8:257)
ICD coding
- I88.9 - Nonspecific lymphadenitis, unspecified
Epidemiology
- Most (but not all) cases are associated with chronic exfoliative or eczematoid skin disease
- Dermatopathic lymphadenitis can occur as a reaction to mycosis fungoides / Sézary syndrome
- Men are affected twice as frequently as women
Sites
- Axillary and inguinal lymph nodes are most commonly affected
Pathophysiology
- Reaction to drainage of melanin and various skin antigens
Etiology
- Chronic skin irritation
Clinical features
- Enlarged, firm, movable, nontender lymph nodes
- Peripheral blood eosinophilia may be present
- Associated with skin disease
Diagnosis
- Clinical presentation, biopsy and histopathology with immunohistochemistry
- Early involvement by mycosis fungoides can be ruled out by testing for T cell clonality with PCR
Laboratory
- Peripheral blood eosinophilia
Radiology description
- Enlarged lymph nodes
Prognostic factors
- Association with mycosis fungoides confers a poorer prognosis
Case reports
- 5 year old boy with swelling of the neck and warts on his lower jaw (J Pediatr Hematol Oncol 2014;36:e231)
- 10 year old girl with clinical signs indicative of deep neck space infection (Am J Otolaryngol 2009;30:419)
- 10 year old boy with a history of severe eczema and enlarged lymph nodes (Clin Nucl Med 2010;35:872)
- 31 year old woman with pemphigus vulgaris and gradually enlarging masses over the groin (Dermatologica Sinica 2013;31:86)
- 44 year old woman with a 1 year history of a slowly growing right sided parotid mass (J Cutan Pathol 2007;34:195)
- 50 year old woman without any skin disease presenting with dermatopathic lymphadenitis (J Cytol 2016;33:49)
- 56 year old woman with dermatopathic lymphadenitis mimicking breast cancer recurrence (Am J Case Rep 2017;18:1330)
- 63 year old woman with fever, hepatosplenomegaly, axillary lymphadenopathy and generalized erythrodermic eruption (Am J Dermatopathol 2010;32:357)
Treatment
- Treatment of the underlying skin irritation or mycosis fungoides (if present)
Gross description
- Enlarged lymph nodes with firm tan to yellow cut surface
- There may be brown pigmented areas
Microscopic (histologic) description
- Preserved architecture and marked paracortical expansion with irregular nodular pale areas located adjacent to the subcapsular sinuses and capsule
- Early stages also show hyperplastic follicles; in later stages follicles become compressed or atrophic
- High power shows the pale areas composed of interdigitating dendritic cells and Langerhans cells admixed with small lymphocytes, plasma cells, eosinophils and histiocytes
- The histiocytes may be foamy or may contain brown pigment in their cytoplasm
- Pigment is commonly melanin but can be hemosiderin
- Medulla may show plasmacytosis and dilated sinuses with histiocytes, plasma cells and eosinophils
Microscopic (histologic) images
Cytology description
- Polymorphous population of small and large lymphocytes admixed with pigment laden macrophages, immunoblasts, dendritic cells, monocytoid cells, eosinophils and plasma cells
Positive stains
Electron microscopy description
- Interdigitating dendritic cells predominate over Langerhans cells and are differentiated from the latter by: more abundant hyperplastic smooth endoplasmic reticulum, lipid droplets and fibrogranular bodies; more prominent tubulovesicular complexes and melanin granules; lack of Birbeck granules which are characteristic of Langerhans cells
Molecular / cytogenetics description
- Polyclonal population of T cells
- Clonal T cell population favors early involvement by mycosis fungoides
Differential diagnosis
- Classic Hodgkin lymphoma: lacks proliferation of Langerhans cells and interdigitating dendritic cells and characteristically contain Hodgkin / Reed-Sternberg cells
- Mycosis fungoides / Sézary syndrome: aberrant T cell immunophenotype and presence of T cell clone
- Toxoplasma lymphadenitis: epithelioid histiocytes, no interdigitating dendritic cells, no Langerhans cells proliferation
- Viral lymphadenitis: paracortical expansion is a common feature; can be differentiated by the lack of pale staining nodular proliferation of interdigitating dendritic cells and Langerhans cells and viral serology assays
Additional references
- Eur J Dermatol 2014;24:670, Hum Pathol 2013;44:1003, Diagn Cytopathol 2012;40:925
- Older references: Arch Pathol Lab Med 1988;112:1145, Semin Diagn Pathol 1988;5:376, Virchows Arch B Cell Pathol Incl Mol Pathol 1984;45:289, Can Med Assoc J 1955;73:836, Br Med J 1955;1:820, Acta Pathol Microbiol Scand 1951;28:352,
Board review style question #1
Dermatopathic lymphadenitis can be a difficult to distinguish from early lymph node involvement by mycosis fungoides / Sézary syndrome. What is a reliable feature to differentiate the two?
- Extensive lymphadenopathy
- Paracortical expansion with a polymorphous lymphohistiocytic infiltrate
- Presence of skin lesions
- Presence of T cell clone
Board review style answer #1
D. Presence of T cell clone: presence of T cell clone identified by molecular methods is the best way to differentiate dermatopathic lymphadenitis from early lymph node involvement by mycosis fungoides / Sézary syndrome.
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Reference: Dermatopathic lymphadenitis
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Reference: Dermatopathic lymphadenitis