In this study, we describe the clinicopathologic features of pseudolymphomatous infiltrates found within lesions of acrodermatitis chronica atrophicans (ACA). We studied 11 patients (10 females, 1 male, age range 60-88 years). The diagnosis of ACA in all cases was confirmed by clinicopathologic correlation and positive serology for Borrelia. Histopathologic examination revealed prominent, pseudolymphomatous inflammatory cell infiltrates in all cases, with 2 distinct patterns. Eight of 11 cases showed a band-like lymphocytic infiltrate, exocytosis of lymphocytes and a fibrotic papillary dermis, similar to features seen in mycosis fungoides. The other 3 cases showed dense, nodular-diffuse dermal infiltrates with many plasma cells and without germinal centers. The plasma cells expressed both kappa and lambda immunoglobulin light chains with a polyclonal pattern in all 3 cases. In conclusion, ACA may present with pseudolymphomatous infiltrates showing both a T-cell and, less frequently, a B-cell pattern. These lesions need to be distinguished from a cutaneous lymphoma. In the context of the knowledge of Borrelia-associated cutaneous lymphomas, follow-up seems advisable in these cases.

Some cases of specific cutaneous manifestations of acute myelogenous leukemia (AML) may mimic inflammatory dermatoses both clinically and histopathologically, presenting with an inconspicuous maculopapular eruption and with only sparse dermal infiltrates. The authors studied the histopathological and immunohistochemical features of 17 biopsies from 16 patients (11 men and 5 women, age range 15-85 years) presenting with minimal skin infiltrates as the first manifestation of AML or as first sign of recurrence after complete remission of the disease. In all cases, the diagnosis of leukemia has been confirmed by bone marrow examination. Two of these cases had been sent to one of us for second expert consultation. Patients presented with generalized, exanthematic maculopapular eruptions, sometimes with a hemorrhagic note, that were mostly interpreted clinically as drug reactions. Histopathologically, the lesions showed sparse, superficial, and mid-dermal infiltrates with minimal perivascular and periadnexal accentuation. Infiltrating cells consisted mostly of neoplastic monocytoid elements with only few reactive lymphocytes and histiocytes. Immunohistochemical stainings revealed in the majority of cases positivity for CD68 (14 of 16 patients), naphthol chloroacetate esterase (NaSDCl) (7 of 10 patients), and myeloperoxidase (6 of 9 patients). Other markers tested were positive only in a minority of cases. These cases represent a pitfall both in the clinical and in the histopathological diagnosis of cutaneous AML. Accurate morphologic and phenotypic correlation together with a high index of suspicion allows a precise diagnosis in these unconventional cases.

In this African study inflammatory conditions are the main burden of skin diseases leading to a diagnostic biopsy. Our findings provide further evidence that KS, primarily related to the high prevalence of HIV infection is an epidemiological problem. Both SCC and basal cell carcinoma represent another relatively common malignant cutaneous neoplasms, reflecting the presence of specific populations at risk. The challenging spectrum of histological diagnoses observed in this specific African setting with basic working conditions shows that development of laboratory services of good standards and specific training in dermatopathology are urgently needed.

Extranodal natural killer (NK)/T-cell lymphoma, nasal type, is a rare type of cytotoxic lymphoma involving mainly the upper aerodigestive tract and associated with Epstein-Barr virus. The disease has usually a poor prognosis related to several factors. The skin is the second most common affected organ, and cases may be localized to the skin only without any other extracutaneous manifestations. Although primary cutaneous cases may have a better prognosis, survival usually is still poor. We report a case of primary cutaneous extranodal NK/T-cell lymphoma, nasal type, in a 77-year-old woman with an indolent course for more than 22 years and still limited to the skin.