3.3.14 Pseudolymphomas (not Borrelia induced)

Grading & Level of Importance: B




Lymphocytic infiltration, lymphoid hyperproliferation.


Clear epidemiological data for borrelia lymphocytoma or other subtypes is lacking.


Reactive pseudolymphomatous infiltrate of B-, T-, and combined T/B-cell type with or without follicular structures in the dermis and subcuti, mimicking malignant lymphomas.

Aetiology & Pathogenesis

In pseudolymphoma B - and T- lymphocytes and other inflammatory cells accumulate in the dermis and subcutis as a reaction to stimuli of different origin. Often a causative agent is missing. Cutaneous pseudolymphoma with known etiology include reactions to tattoo dyes, arthropods, systemic medications, infections or vaccinations. A specific subset of B- cell type pseudolymphoma, borrelial lymphocytoma, primarily in Europe in areas endemic for the tick Ixodes ricinus with infection by Borrelia burgdorferi subsp afzelii and garinii.

Signs & Symptoms

Different forms: localized erythematous macules sometimes confluent, nodule, plaque, disseminated; occasionally with lymphadenopathy.


In borrelia lymphocytoma lesions indolent soft blue-red nodule up to 5 cm. Post scabies lymphocytomas localized or often disseminated. T-cell pseudolymphomas occur with localized plaques, nodules and disseminated papules or annular pattern.


Sites of predilection:  in borrelia lymphocytoma loose skin (ear, nipple, scrotum); T- or B-/T- pseudolymphomas may be localized (facial), single or multiple all over the body incl. erythrodermas.


No international classification as compared to malignant cutaneous lymphomas.


B -, T- and B-/T_ cell dominated subtypes.

Laboratory & other workups

Borrelia IgG and IgM titers raised in Borrelia lymphocytoma. In lymphocytic infiltration immunserology to exclude lupus erythematosus and blood count for leukemic infiltrate.


No specific other test.


Most important to differentiate the subtypes of pseudolymphomas and to exclude primary or secondary malignant B-or T-cell lymphomas, eosinophils and plasma cells in a polymorphous pattern suggest pseudolymphoma.


Depends on subtype. In borrelia lymphocytoma after adequate 2nd stage oral doxycycline over 3 weeks slowly fading of lesion(s).


Cessation of drugs lead after weeks or months depending on persistent metabolites to resolution.




Clinical features, serology, histology, PCR.

Differential diagnosis

Malignant primary and secondary B- / T- cell lymphomas, disseminated cutaneous sarcoidosis, stage II syphilis.

Prevention & Therapy

Depending on subtype.


Antibiotics (doxycycline 100 mg b.i.d. for 21 days) in borrelia lymphocytoma.


Cessation of responsible drugs. Topical mid and high potency corticosteroids. Occasionally intralesional steroids.



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