Extranodal involvement is frequent in MCL, particularly in the bone marrow, gastrointestinal tract, and Waldeyer’s ring. Cutaneous involvement by MCL typically occurs in the setting of systemic disease with only 18 cases that have been previously described in the literature. It is said that cutaneous dissemination can be present in up to 17% of patients with stage IV disease.¹⁰ Primary cutaneous involvement by MCL has been the subject of isolated case reports.^{1,10,11,12,13,14,15,16} A primary cutaneous lymphoma, according to the WHO–EORTC definition,^17,18 is one that presents in the skin with no evidence of extracutaneous disease at the time of presentation. A total of five cases of primary cutaneous MCL are described and of those three were classified as blastoid variants, one of the reported more aggressive forms of the disease. None of these cases developed systemic involvement after more than 20 months of clinical follow-up. Motegi et al.¹⁹ reviewed the documented cases of cutaneous involvement by MCL. Of the 17 cases described, 14 of the patients exhibited skin lesions at the time of the initial diagnosis. The most common skin locations included the trunk (most common site), followed by the face, arms, thighs, legs, and scalp. The lesions were frequently described as nodular, but other cutaneous presentations included: macular, maculopapular, tumoral, plaques, and subcutaneous nodules (Fig. 33-1A–C).¹⁹ We have also found similar locations being most common in the extremities and the face (data not published) where most of the cases presented as nodules or tumors. In addition to the neoplastic dissemination of the tumor on the skin, occasional paraneoplastic syndromes with cutaneous manifestations have been associated to MCL. Crops of pruritic papules throughout the body have been described in this setting. The biopsies of these lesions show a mixed inflammatory infiltrate with foci of folliculitis and the presence of eosinophils.^20,21,22

The mean survival time as measured from the time of the diagnosis to death or last clinical follow-up is 63.5 months (range, 26 to 182 months). The mean time to recurrence as measured from the diagnosis to first clinical recurrence is 43.6 months (range, 11 to 132 months). The mean time of the diagnosis to the diagnosis of cutaneous involvement by MCL is 34.83 months (range, 1 to 132 months). The skin is the most common first site of recurrence of the disease in the majority of patients. All patients are typically treated with systemic chemotherapy (typically R-CHOP regimens). Some cases have shown clinical responses to radiotherapy and the novel tyrosine-kinase inhibitor ibrutinib²³ and lenalidomide.²⁴