Myelodysplasia cutis masquerading as granulomatous dermatitis.

Myelodysplastic syndromes (MDS) are a group of clonal hematopoietic neoplasms resulting from mutations in stem cells. They carry a risk of transformation to acute myeloid leukemia. Cutaneous manifestations of MDS, including myelodysplasia cutis or infiltration by MDS tumor cells, are rare, but significantly associated with increased risk of progression to high-grade myeloid tumors. The clinical and histopathologic differential diagnosis for myelodysplasia cutis includes interstitial granulomatous dermatitis (IGD), a reactive granulomatous dermatitis (RGD) associated with systemic diseases including rheumatologic diseases, and hematologic malignancy like MDS. We report a patient with MDS who presented with myelodysplasia cutis masquerading as IGD both in a clinical and histopathological manner.

Clonal cutaneous and neurosyphilis: A pitfall in pseudolymphoma diagnosis.

Syphilis is a sexually transmitted infectious disease caused by the bacterium Treponema pallidum and can cause a wide variety of cutaneous manifestations, most commonly, a papulosquamous eruption of the trunk and extremities. Treatment with penicillin is curative. We report a case of a 69-year-old man who presented with recent onset of blurry vision and a nonpainful, nonpruritic eruption of pink-to-violaceous dermal nodules on his upper trunk and upper extremities. Biopsies of two separate locations revealed a dense superficial and deep perivascular atypical lymphocytic infiltrate with admixed plasma cells, histiocytes, and eosinophils. Some scattered cells expressed CD30, PD1, BCL-6, and ICOS. T-cell receptor (TCR)-rearrangement showed an identical TCR-gamma clone between both biopsy specimens. The patient was subsequently seen by ophthalmology and diagnosed with acute anterior uveitis. Rapid plasma reagin was reactive and cerebrospinal fluid studies showed findings consistent with a diagnosis of neurosyphilis. A T. pallidum immunostain of the skin biopsies was performed upon re-review, and was diffusely positive for spirochetes at the dermal-epidermal junction and within injured vessels. The patient was treated with penicillin G with near-resolution of his skin lesions. This case highlights the unusual ability of syphilis to mimic a T-cell lymphoma with matching clones across two different biopsy sites.

Primary Cutaneous CD4-Positive Small/Medium T-Cell Lymphoproliferative Disorder Mimicking Jessner Lymphocytic Infiltrate and Tumid Lupus-A Report of Two Cases.

ABSTRACT: Primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorder is a benign lymphoproliferative disorder composed of small-sized to medium-sized pleomorphic cells expressing a follicular helper T-cell phenotype. Jessner lymphocytic infiltrate and tumid lupus are cutaneous conditions characterized by the presence of rich dermal lymphocytic infiltrates with a superficial, deep, perivascular and periadnexal distribution that include copious amounts of dermal mucin deposition. We report 2 cases of primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorder presenting with markedly increased dermal mucin, mimicking both Jessner lymphocytic infiltrate and tumid lupus and provide a review of the differential diagnosis and highlight key distinguishing features.