Feline and Canine Cutaneous Lymphocytosis: Reactive Process or Indolent Neoplastic Disease?

Cutaneous lymphocytosis (CL) is an uncommon and controversial lymphoproliferative disorder described in dogs and cats. CL is generally characterized by a heterogeneous clinical presentation and histological features that may overlap with epitheliotropic lymphoma. Therefore, its neoplastic or reactive nature is still debated. Here, we describe clinicopathological, immunohistochemical, and clonality features of a retrospective case series of 19 cats and 10 dogs with lesions histologically compatible with CL. In both species, alopecia, erythema, and scales were the most frequent clinical signs. Histologically, a dermal infiltrate of small to medium-sized lymphocytes, occasionally extending to the subcutis, was always identified. Conversely, when present, epitheliotropism was generally mild. In cats, the infiltrate was consistently CD3+; in dogs, a mixture of CD3+ and CD20+ lymphocytes was observed only in 4 cases. The infiltrate was polyclonal in all cats, while BCR and TCR clonal rearrangements were identified in dogs. Overall, cats had a long-term survival (median overall survival = 1080 days) regardless of the treatment received, while dogs showed a shorter and variable clinical course, with no evident associations with clinicopathological features. In conclusion, our results support a reactive nature of the disease in cats, associated with prolonged survival; despite a similar histological picture, canine CL is associated with a more heterogeneous lymphocytic infiltrate, clonality results, and response to treatment, implying a more challenging discrimination between CL and CEL in this species. A complete diagnostic workup and detailed follow-up information on a higher number of cases is warrant for dogs.

Canine and Feline Cutaneous Lymphocytosis: Reactive Process or Indolent Neoplastic Disease?

Cutaneous lymphocytosis (CL) is an uncommon and controversial lymphoproliferative disorder described in dogs and cats. CL is generally characterized by a heterogeneous clinical presentation and histological features that may overlap with epitheliotropic lymphoma. Therefore, its neoplastic or reactive nature is still debated. Here, we describe clinicopathological, immunohistochemical and clonality features of a retrospective case series of 19 cats and 10 dogs with lesions histologically compatible with CL. In both species, alopecia, erythema and scales were the most frequent clinical signs. Histologically, a dermal infiltrate of small to medium-sized lymphocytes, occasionally extending to the subcutis, was always identified. Conversely, when present, epitheliotropism was generally mild. In cats, the infiltrate was consistently CD3+; in dogs, a mixture of CD3+ and CD20+ lymphocytes was observed only in 4 cases. The infiltrate was polyclonal in all cats, while BCR and TCR clonal rearrangements were identified in dogs. Overall, cats had a long-term survival (median overall survival=1080 days) regardless of the treatment received, while dogs showed a shorter and variable clinical course, with no evident associations with clinicopathological features. In conclusion, our results support a reactive nature of the disease in cats, associated with prolonged survival; despite a similar histological picture, canine CL was associated with a more heterogeneous lymphocytic infiltrate, clonality results, and response to treatment.

Sweet’s syndrome and mucosal prolapse polyps in a male patient with ulcerative colitis

Background Sweet’s syndrome (SS), also known as acute febrile neutrophilic dermatosis, is a rare neutrophilic dermatitis characterized by pyrexia, neutrophilia and painful papulonodular lesions with a neutrophilic dermal infiltrate. Case presentation We presented a case report of classical SS associated with ulcerative colitis (UC) and mucosal prolapse polyps (MPPs) in a male patient. Conclusions The particularity of this case is the occurrence of MPPs in a male patient with UC and classical SS. We also discussed whether this patient with concurrent Epstein–Barr virus infection could be treated with corticosteroids.

Immunohistochemistry Aids in the Diagnosis of Blastic Plasmacytoid Dendritic Cell Neoplasm in a Patient with Multiple Cutaneous Plaques and Nodules

Introduction/Objective Blastic Plasmacytoid Dendritic Cell Neoplasm (BPDCN) is a rare hematologic malignancy of plasmacytoid dendritic cell precursors with an estimated incidence of 0.04 cases per 100,000 in the US. Given the cutaneous tropism of BPDCN, it should be differentiated from other CD56+ hematopoietic neoplasms with skin involvement such as CD56+ AML, extranodal NK/T-cell lymphoma, and other T-cell lymphomas. Methods/Case Report A 71-year-old male presented to the emergency department with asymptomatic, pink- violaceous plaques/nodules on the trunk for 3 months. One month prior, a dermatologist diagnosed epidermal inclusion cysts that were left untreated. The nodules progressed and a course of steroids prescribed by a primary care physician provided short term improvement before the lesions flared again. Review of systems and vitals were normal. Biopsies of representative lesions sent for histologic examination showed a diffuse dermal infiltrate of small to medium atypical cells with irregular nuclear contours, fine chromatin, one to several nucleoli and scant cytoplasm. Immunohistochemistry showed these cells were positive for CD2, CD4, CD56 and CD45 with strong expression of BCL2 and focal CD123. The cells were negative for CD3, CD20, CD79a, CD8, CD30, ALK-1, MUM-1, CD10, Cyclin- D1, C-MYC, EBER, BCL6, Langerin, Granzyme, TIA1, CD68, CD163, MPO, and Lysozyme. The histology and immunoprofile were consistent with BPDCN. A bone marrow biopsy showed cells with similar morphology and staining pattern, including expression of CD123.Treatment with chemotherapy and Tagraxofusp, was initiated. Within a week, the patient showed near resolution of cutaneous lesions. Repeat bone marrow aspirate and flow cytometry a month later showed no malignant cells. Results (if a Case Study enter NA) NA Conclusion We present this case as a rare hematologic malignancy with a challenging clinical and histopathologic diagnosis. The histologic findings suggested either a high grade myeloid or lymphoid malignancy. The combination of CD3-/CD56+/CD4+/CD123+ in the lesional cells helped establish the diagnosis of BPDCN, allowing for prompt treatment.

Progressive Nodular Histiocytosis: Report of a Case and Review of the Literature

Progressive nodular histiocytosis (PNH) is a rare condition characterized by progressive eruption of multiple yellowish-brown papules and nodules on the skin and mucous membranes. We present the case of a 37-year-old Caucasian man with gradually increased appearance of nodular lesions on the forehead and right temple. These lesions were initially diagnosed as xanthomas and did not respond to intralesional injections of triamcinolone. Additional biopsy revealed an intense dermal infiltrate of foamy mononuclear epithelioid cells with a minor admixture of plasma cells, lymphocytes, and scattered multinucleated giant cells. On immunohistochemical staining, the lesional cells were positive for CD163 and CD68 and negative for CD1a, thus confirming a mononuclear-macrophage lineage. The clinical presentation and the histological impression lead to the diagnosis of PNH. This condition could be challenging, mimicking microscopically similar lesions of the non-Langerhans cell histiocytosis group. Although uncommon, PNH stands out due to its clinical and microscopic features and should be taken into consideration in the differential diagnosis of cutaneous histiocytoses.

A rare case of scrofuloderma along with lupus vulgaris

Cutaneous forms of tuberculosis (TB) are rare, comprising about 1-1.5% of all cases, and show a wide range of clinical manifestations. Here we present a case of a patient with left cervical ulcerated lymphadenopathy associated with a violaceous plaque in the area of the manubrium of sternum. We performed a biopsy of the plaque for histopathology, a polymerase chain reaction (PCR) to test for mycobacteria and a smear of the ulcerated lymph node. Histopathology results showed a dermal infiltrate consisting of epithelioid granulomas without necrosis, PCR was negative and the culture was positive for M. tuberculosis. We made the diagnosis of scrofuloderma associated with lupus vulgaris. The patient was treated with an anti-tuberculous therapy with clinical regression of the lesions. Our case emphasizes the importance of recognizing that tuberculosis can occur as a primary cutaneous pathology, with a challenging diagnosis that requires the correlation of clinical findings with diagnostic testing.

Generalised eruptive histiocytosis preceded by systemic symptoms

Generalised eruptive histiocytosis is a rare proliferative disease that typically presents with indolent cutaneous eruptions. We describe the case of a 73-year-old man presenting with diffuse, asymptomatic crops of pink to dusky red papules preceded by general malaise, myalgias, fluctuating fever, chills, and weight loss. Histological evaluation revealed a non-Langerhans cell histiocytic dermal infiltrate with spindle cell features and chronic inflammation, reactive for CD68 and negative for both S100 and CD1a. Malignancy screening was negative. This report aims to highlight a unique presentation of generalised eruptive histiocytosis, emphasise histological findings, and discuss considerations for malignancy screening.

Penile annular and scrotal eczematoid syphilids with penile chancre redux

We describe a 17-year-old man who developed penile annular and scrotal eczematoid syphilids with penile chancre redux. Dermoscopy showed linear-irregular and hairpin vessels with white scales in annular lesions. Histopathology displayed psoriasiform hyperplasia with perivascular lymphoplasmacytic dermal infiltrate. Rapid plasma reagin and Treponema pallidumparticle agglutination assays were positive. The lesions disappeared after intramuscular benzathine penicillin.

Majocchi’s Granuloma on the Forearm Caused by Trichophyton tonsurans in an Immunocompetent Patient

Majocchi's granuloma is an uncommon fungal infection of the dermis and subcutaneous tissue. The most frequently identified cause of Majocchi’s granuloma is anthropophilic Trichophyton rubrum, and it is most commonly located on the anterior aspect of the lower limbs in women. Here, we report a case of Majocchi’s granuloma on the forearm, a site that is rarely involved, in a 62-year-old woman who had been bitten by a dog. Histological examination revealed a dense dermal infiltrate composed of lymphoplasmacytic cells and neutrophils, with hyphae in the dermis. The presence of the fungus, Trichophyton tonsurans, was confirmed by mycological examination and molecular methods. Therefore, histological and mycological examination confirmed the diagnosis of Majocchi’s granuloma. The patient was treated with local moxibustion and itraconazole, 200 mg/day, for 60 days, which facilitated a complete resolution of the lesions.