Generalized Reddish Skin Nodules.

Area of Science:

• Dermatology
• Oncology
• Pathology

Background:

• Nodular red skin lesions present a diagnostic challenge with a broad differential diagnosis.
• Erythema nodosum is a common consideration, but thorough workup is essential for accurate diagnosis.
• Cutaneous lymphomas, particularly diffuse large B-cell lymphoma (DLBCL), are rare but important considerations for unexplained skin nodules.

Purpose of the Study:

• To present a case of cutaneous diffuse large B-cell lymphoma (DLBCL) presenting as painful, dark red skin nodules.
• To emphasize the importance of histopathology and immunohistochemistry in diagnosing rare cutaneous lymphomas.
• To highlight DLBCL as a differential diagnosis for unexplained red skin nodules.

Main Methods:

• Clinical presentation of a 60-year-old female with painful, dark red skin nodules, fever, arthralgia, and weight loss.
• Laboratory investigations including complete blood count, liver function tests, and serological tests for viral antigens.
• Histopathological examination and immunohistochemical staining (CD45, CD20, CD10, Ki67, CD3, CD56, CD30, Granzyme) of a skin nodule biopsy.

Main Results:

• Histopathology revealed cutaneous lymphoma, with positive immunohistochemical markers for CD45, CD20, CD10, and Ki67 (>70%).
• The patient was diagnosed with Cutaneous Diffuse Large B-cell Lymphoma (DLBCL).
• Skin involvement in DLBCL is uncommon, occurring in only 3.3% of cases at presentation.

Conclusions:

• Cutaneous DLBCL can present as non-specific red skin nodules, necessitating a high index of suspicion.
• Immunohistochemistry is crucial for differentiating cutaneous lymphomas from other skin conditions.
• Early and accurate diagnosis of cutaneous lymphoma is vital for appropriate management and prognosis.