A case of a primary cutaneous diffuse large B‐cell lymphoma, leg type

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An 82 year‐old woman referred to our department for violaceous, multiple, and confluent nodules arised on her left leg 1 month before. The lesions were partially ulcerated and no clinical lymphadenopathy was noticed (Figure 1A,B). No symptoms, such as pain or burning sensations, were reported by the patient. She has been suffering from unilateral lymphedema of the left inferior limb, which occurred 1 year ago. Regarding her past medical history, she referred previous surgery for vulvar squamous cell carcinoma (2015), and she has been treated for heart failure with beta‐blockers, angiotensin‐converting enzyme‐inhibitor, and diuretics.

Figure 1.

A‐B, Multiple and confluent nodules arised on her left leg 1 month before. The lesions were partially ulcerated and no clinical lymphadenopathy was noticed

An incisional biopsy was planned in order to rule out malignancy. The histological examination with haematoxylin and eosin staining showed a diffuse proliferation of pleomorphic, medium to large lymphocytes in the deep dermis with mitosis, too. No alteration in the corresponding epidermis was noticed (Figure 2A‐D). Immunohistochemistry was positive for CD20, Bcl‐2, Bcl‐6, and ki‐67 (Figure 2E‐H). All the results led to the diagnosis of a primary cutaneous diffuse large B‐cell lymphoma, leg type (PCDLBCL‐LT). The following total body was computed tomography (CT)‐scan performed reported no other lesions. The patient was treated with systemic corticosteroids (deltacortene 40 mg die) for 4 days and she is currently on follow‐up at our Department.

Figure 2.

A‐D, The histological examination with haematoxylin and eosin staining showed a diffuse proliferation of pleomorphic, medium to large lymphocytes in the deep dermis with mitosis, too. No alteration in the corresponding epidermis was noticed. E‐H, Immunohistochemistry was positive for CD20, Bcl‐2, Bcl‐6, and ki‐67

From 20% to 25% of primary cutaneous lymphoma include B‐cell lymphomas and most of the cases are represented by the three main types, one of which is the PCDLBCL‐LT.1 Usually, patients present a vascular tumour‐ or panniculitis‐like clinical picture, with red to violaceous plaques located mainly on the lower limbs.2, 3 The patients' mean age of onset is generally advanced and they often show relapses and extracutaneous involvement.4

Histology shows diffuse infiltrates of cells with a centroblast or immunoblast aspect with mitotic activity3 and, on immunohistochemistry, a high percentage of cases of Bcl‐.2 expression.4 Treatment regimen is based on a more aggressive approach with either systemic or local chemotherapy (cyclophosphamide, doxorubicin, and vincristine), and rituximab therapy associated or not with local radiotherapy depending on the patient's comorbidities.2 The estimated 5‐year disease‐specific survival rate is about 41%.4

The case herein described is a rare condition, as, until now, 13 cases of primary cutaneous lymphoma associated with chronic lymphedema have been reported.5 Not only for lymphoma but also for other skin tumour (eg, Kaposi sarcoma), chronic lymphatic stasis is thought to be a risk factor for local immune dysfunction and, subsequently, neoplastic disorders.5, 6 In fact, local immune system is impaired by chronic lymphedema of any origin (eg, congenital or acquired), as immunocompetent cell (lymphocytes and Langerhans cells) trafficking is impeded.7 This damage may trigger secondary angiogenesis with development of collateral hematic and lymphatic vessels and, eventually, vascular neoplasia.7

Here, we report a rare case of PCDLBCL‐LT without extracutaneous dissemination arising on a chronic unilateral lymphedema of the leg and we once again underline the importance of a prompt clinical and histological differential diagnosis of possible neoplasia in susceptible localization.