Panniculitis: Recent developments and observations

Abstract

Dermatopathologists rarely greet a biopsy of panniculitis with total confidence that a specific, definitive diagnosis will be rendered. As with many other areas in dermatopathology, our understanding of the pathogenesis of many forms of panniculitis is incomplete. This article examines a subset of panniculitis primarily from a pathogenetic standpoint, with the intention of providing a differential diagnosis for those cases in which ischemic changes are seen in the subcutis. The diverse group of conditions evoked by this approach also shares the distinction of having been the focus of nosologic and causative controversy, both historically and currently. In particular, stasis-associated sclerosing panniculitis, vascular calcification-cutaneous necrosis syndrome (calciphylaxis), oxalosis, and nodular vasculitis-erythema induratum are examined in depth. Erythema nodosum and variants, other granulomatous panniculitides, and panniculitides showing cytophagocytosis are also discussed with current perspectives.

Subcutaneous lymphoid hyperplasia arising at site of ethnic scarifications and mimicking subcutaneous panniculitis-like T-cell lymphoma

“…Of the various diseases featuring such histological alterations, one of the conditions that most closely resembles the present lesion is SPTCL [3,7,11,14,16]. Indeed, many of the histological features that are observed in this case may also be found in SPTCL.…”

“…Although SPTCL may occasionally behave in a more indolent way [11], it is mostly a highly malignant neoplasm that pursues an aggressive course, usually associated with severe clinical symptoms [3,7,11,14,16].…”

“…This rare tumour preferentially involves the subcutaneous tissue of the extremities and/or of the trunk, and a significant number of cases are complicated by a haemophagocytic syndrome [3,7,11,14,16]. Histologically, this neoplastic disorder is made up primarily of small-or medium-sized lymphocytes that involve the subcutaneous fat in a way very similar to that of a lobular panniculitis [7,11,14,16]. When investigated using immunohistochemistry, most SPTCL cases show a CD3+, CD4-, CD8+, CD56-T-cell phenotype and consistently express markers of cytotoxic T lymphocytes, such as cytolytic granule-associated protein TIA-1, perforin, or granzyme B.…”

Resistant Erythema Nodosum-Remembering an Old Treatment (Potassium Iodide)

“…Although Miescher's granulomata are a useful indicator of EN the typical radial granulomas are present in less than 75% of cases. As suggested by Miescher, they are seen in very early disease as early as day 2 therefore biopsy timing is crucial for their detection [3].…”

Neutrophilic Panniculitis: Algorithmic Approach to a Heterogeneous Group of Disorders

“…51 Miescher radial granulomas, referring to small aggregates of histiocytes and neutrophils surrounding a central cleft of stellate or banana shape (Figure 8, B), 52 may be used as a diagnostic clue for erythema nodosum, although they have occasionally been reported in other dermatoses as well. 53 CONCLUSION Evaluation for neutrophilic panniculitis requires careful attention to the pattern of inflammation, the type of fat necrosis present, any evidence of vascular damage, and all other relevant histopathologic features. Because neutrophilic panniculitis may be the initial manifestation of an underlying systemic disease, correlation with clinical history and laboratory findings is also of paramount importance.…”