"White" network in Spitz nevi and early melanomas lacking significant pigmentation.

BACKGROUND: Spitz nevi and early melanomas lacking significant pigmentation exhibit overlapping dermoscopic patterns of regularly arranged dotted vessels over a pink background. Although white network has been described in both tumors, little is known about the frequency of this pattern in both tumors. OBJECTIVE: We sought to compare the frequency of white network in Spitz nevi and early melanomas lacking significant pigmentation and to correlate this feature with histopathology. METHODS: Two independent dermoscopists scored the presence of white network in a series of retrospectively collected images of histopathologically diagnosed cases of Spitz nevi and melanomas, dermoscopically typified by dotted vessels. RESULTS: A total of 65 cases including 39 melanomas (median thickness 0.4 mm) and 26 Spitz nevi were analyzed. Patients with Spitz nevi were significantly younger compared to patients with melanoma (mean age: 26.8 vs 51.2 years, respectively; P < .001). The 2 observers scored white network being present in 23 (88.5%) and 24 (92.3%) Spitz nevi compared with 10 (25.6%) and 8 (20.5%) cases of 39 melanomas, respectively (P < .001). Interobserver agreement for white network was good (kappa = 0.67; 95% confidence interval 0.44-0.90). Histopathologically, elongated rete ridges were observed in 22 (88.5%) Spitz nevi and 11 (36.7%) melanomas (P < .001). LIMITATIONS: We did not evaluate other dermoscopic-histopathologic correlates commonly seen in Spitz nevi and melanomas in our study. CONCLUSION: Although white network occurs at significantly higher frequency among hypopigmented/amelanotic Spitz nevi compared with early melanoma, it is not exclusively seen in Spitz nevi. Thus, excision of melanocytic tumors showing this pattern is mandatory.

Histopathology of panniculitis--aspects of biopsy techniques and difficulties in diagnosis.

BACKGROUND: Clinical and histologic diagnosis of panniculitis may be difficult. The patients usually present with erythematous subcutaneous nodules with or without additional symptoms. If a skin biopsy does not include enough subcutaneous fat, histopathologic assessment is limited and the correct diagnosis may be delayed and require further sampling. PATIENTS AND METHODS: To illustrate the difficulties in the diagnosis of panniculitis, we performed a retrospective examination of four patients with different forms of panniculitis. RESULTS: In two patients with subcutaneous panniculitis-like T cell lymphoma and lupus panniculitis, the correct diagnosis could only be ascertained after a delay of several months because repeated biopsies had to be obtained throughout the course of disease. In two further patients with cold panniculitis and pancreatic panniculitis, clinicians did not even suspect an inflammatory process in the subcutaneous tissue. The correct diagnosis was made with a deep punch biopsy that included subcutaneous fat. CONCLUSIONS: On the one hand, these examples demonstrate the importance of sampling subcutaneous tissue when obtaining routine punch biopsies. On the other hand, in cases where the diagnosis is uncertain, it is necessary to perform large and deep incisional biopsies.

Primary Cutaneous Gamma-Delta T-Cell Lymphoma With Long-Term Indolent Clinical Course Initially Mimicking Lupus Erythematosus Profundus.

Primary Cutaneous Gamma-Delta (γδ) T-Cell Lymphoma (PCGDTCL) is a rare primary cutaneous lymphoma of aggressive nature. Only a few cases with an initially indolent course over years have been published. PCGDTCL can mimic diseases with benign behavior in their clinical and histopathological presentation, such as lupus erythematosus profundus, but also other lymphomas, for example subcutaneous panniculitis-like T-cell lymphoma. In our patient, the results of histopathological, immunofluorescence microscopy, and clinical examinations of early lesions first led to the diagnosis of lupus erythematosus profundus. Two years after this diagnosis and 6 years after the first clinical symptoms appeared, the disease progressed with erosive and ulcerating plaques and a PCGDTCL with hemophagocytic syndrome with an aggressive course was diagnosed. A distinct correlation of clinical, histopathological, immunohistochemical, and molecular-pathological examinations is needed to differentiate between the potentially malignant and benign diseases. Re-biopsies of different skin lesions in uncertain cases are strongly indicated. This case demonstrates that an indolent clinical phenotype can precede an aggressive clinical course in PCGDTCL.