diffuse large b cell lymphoma prognosis | Large-cell low-limb B diffuse cutaneous lymphoma

Large-cell low-limb B diffuse cutaneous lymphoma

Introduction
Low-limb, diffuse large-cell (LBDGC) B lymphomas preferentially occur in women after 70ans and elect the lower limbs. They produce tumors that are often multiple, increasing in volume, purplish-red, localized or scattered.

Observation
A 75 years patient with no history consults for the appearance of hard and painless centimetre subcutaneous nodules that have been evolving for a month without any associated general signs (no weight loss, no night sweat or fever), at the trunk, back, neck, of the arms. Only palpation allows to objectify these nodules because the skin in the eye is normal and the deep localization Dermo-hypodermic. There is no lymphadenopathy on the exam. A first resection biopsy of an arm nodule reveals a deep dermal localization of diffuse B lymphoma with large cells CD20 +, Bcl2 +, Bcl6 +, CD10 −, CD5 −. The biopsied nodule was completely involué a month later. The diagnosis is confirmed again on a second blood sample at the neck level. The extension balance by TEP recovers multiple subcutaneous nodular foci of the trunk and the root of the lower limbs associated with a right iliac hypermetabolic lymphadenopathy. The Myelogram regains an overrepresentation of the non-myeloid contingent consistent with lymphoid hemopathy and the BOM does not find medullary invasion.

Discussion
Our case of cutaneous lymphoma is atypical in its presentation (nodules not visible to the naked eye) and its localization (mainly the trunk). The involution of the nodules is classical but rare. We retained the diagnosis of primary cutaneous B lymphoma because the only lymphadenopathy found is the drainage territory of the subcutaneous nodules of the lower limb root. Indeed the nosological difference between a ganglionic LBDGC with cutaneous localization and a primitively cutaneous LBDGC is based on a negative extension balance to the diagnosis for the initially cutaneous lymphoma. However, their prognosis is different: The primitively cutaneous form has an intermediate prognosis, less aggressive than the ganglion forms but the prognosis is aggravated by their occurrence in older subjects [1]. Similarly, the seat of the lesions is a prognostic factor, the 3ans-specific survival rate is 77% in the case of tumours not affecting the lower limbs (compared to 43% for the lower limbs) [2]. The prognosis is related to ganglionic or visceral release (cerebral in particular) but also to skin progression responsible for altered general condition or septic complications. However, these factors do not affect treatment [1], which remains the same in both cases: RCHOP chemotherapy at first thought in the absence of comorbidity. Treatment initiated in this patient with excellent clinical and morphological response after 3 cures (disappearance of subcutaneous and ganglionic metabolic foci).

Conclusion
Clinical descriptions of diffuse B lymphomas with large skin cells of the lower limb type are quite stereotypical but our case illustrates the sometimes atypical manifestations in terms of presentation and localization. Despite differences with Ganglionic B lymphoma at the nosological plane, therapy remains the same.