Dermatopathic Lymphadenitis.

To the Editor: Dermatopathic lymphadenitis (DL) represents a rare benign lymphatic hyperplasia commonly associated with exfoliative or eczematoid dermatitis. DL was also reported to be a potential mimicker of lymphoma.[1] Here, we report the 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computer tomography (PET/CT) results and the histological findings of a 40-year-old female patient with DL.

A 40-year-old female with a history of chronic vitiligo and urticaria was admitted to our hospital because of worsening recurrent fever and chronic joint pain for more than 2 years. She reported that her symptoms had aggravated in the month prior to her presentation. Her body temperature was 39.3°C at the time of admission. Physical examination revealed scattered nonblanchable erythematous papules coalescing into plaques, most prominently in the upper chest and bilateral upper extremities. Generalized lymphadenopathy was noted, with the largest lymph node measuring up to 3 cm in short axis found in the axilla. The lymph nodes were firm, nontender, and mobile. Laboratory tests revealed the following: White blood cell count of 16,000 cells/mm3 (normal range: 4000–10,000 cells/mm3), C-reactive protein of 106 mg/L (normal range: 0–8 mg/L), erythrocyte sedimentation rate of 140 mm/h (normal range: 1–20 mm/h), ferritin of 7789.47 ng/ml (normal range: 4.63–204.00 ng/ml), immunoglobulin E of 1113 ng/ml (normal range: 0–619.40 ng/ml), and lactate dehydrogenase of 371.6 U/L (normal range: 109.0–245.0 U/L). Bone marrow biopsy demonstrated bone marrow hyperplasia with significantly increased megakaryocyte distribution.

Due to the clinical suspicion of lymphoma, the patient underwent 18F-FDG PET/CT (18F-FDG was produced by the Eclipse RD cyclotron, Siemens Medical Solutions USA, Inc., USA; and PET/CT scanner was also from the Siemens Medical Solutions USA, Inc.), and results showed numerous enlarged lymph nodes with FDG avidity in bilateral cervical, supraclavicular, axillary, mediastinal, retroperitoneal, pelvic, and inguinal regions [Figure 1]. Left cervical lymph node biopsy was performed and pathology revealed lymphoid hyperplasia along with normal lymphoid tissue [Figure 2a and b]. Immunohistochemical analysis showed positive CD68 and S100 [Figure 2c and d]. The patient was subsequently diagnosed as DL by pathology examination and was treated with kitasamycin and supportive measures. Her fever resolved and skin symptoms were diminished obviously. At follow-up, one and a half year after her presentation, she remained symptom-free.

Figure 1

18F-fluorodeoxyglucose positron emission tomography/computed tomography images of the patient with dermatopathic lymphadenitis. (a) Maximum intensity projection positron emission tomography image shows extensive 18F-fluorodeoxyglucose-avid lymphadenopathy in bilateral cervical, supraclavicular, axillary, mediastinal, retroperitoneal, pelvic, and inguinal regions. (b-d) Transaxial positron emission tomography/computed tomography fusion images show enlarged cervical, axillary, and inguinal lymph nodes. The largest lymph node measures 24 mm × 12 mm in the right axilla, with maximum standardized uptake value of 12.2.

Figure 2

Histological images of the left neck lymph node of the patient with dermatopathic lymphadenitis. (a and b) lymphoid hyperplasia and structural disorder, paracortical enlargement by T-zone proliferation with pigment laden histiocytes (H and E, original magnification a, original magnification, ×100; b, original magnification, ×200). (c and d) Immunohistochemical staining shows positive cytoplasmic staining for CD68 and S100, respectively (original magnification, ×100).

DL, also known as lipomelanotic reticulosis or Pautrier-Woringer disease, represents a rare form of benign lymphatic hyperplasia associated with most exfoliative or eczematoid inflammatory erythrodermas, including pemphigus, psoriasis, eczema, neurodermatitis, and atrophia senilis.[23] Painless lymphadenopathy accompanied by fever is the most common presentation. It is a self-limited disease often not requiring any therapy.[4]

Diagnosis of DL is mostly based on the lymph node biopsy. In this case, the short axis of the biopsied lymph node exceeded 2 cm in 18F-FDG PET/CT. It is well-known that atypical lymphoid hyperplasia could mimic lymphoma in the clinical hematology practice[5] and it is sometimes difficult to distinguish between lymphoma and DL with PET/CT examination. However, PET/CT can still demonstrate most or all of the involved lymph nodes and provide information about their size, number, distribution, and FDG avidity, which can serve as a valuable guide to lymph node biopsy.

In conclusion, although diagnosis of DL mainly depends on the clinical presentation and lymph node biopsy, 18F-FDG PET/CT, as a sensitive and noninvasive whole-body imaging technique, can be employed as a valuable aid in the diagnostic workup.

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Conflicts of interest

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