CASE REPORT: A 40-year-old Japanese man presented with lower abdominal pain. Computed tomography revealed a prostatic mass; furthermore, prostate core needle biopsy revealed proliferating bland spindle cells, without necrosis or prominent mitoses. Tumour cells were positive for CD34 and progesterone receptor on immunohistochemical analysis; thus, a prostatic stromal tumour of uncertain malignant potential was initially suspected. However, as the tumour cells showed positive immunoreactivity for STAT6, the final diagnosis was an SFT of the prostate. The patient underwent tumour resection, and at the 6-month postoperative follow-up, neither local recurrence nor distant metastasis occurred.
CONCLUSION: For an accurate diagnosis of an SFT of the prostate, STAT6 immunohistochemistry should be conducted for all mesenchymal tumours of the prostate. When STAT6 immunohistochemical analysis is unfeasible, pathologists should be aware that the morphological and immunohistochemical characteristics of SFT variable from case to case and diagnose with combined analysis of several immunohistochemical markers.
CASE REPORT: Herein, we describe and compare three cases of CASTLE, including a case with distant metastasis despite administering postoperative chemotherapy. Thus, the mechanisms underlying metastasis of CASTLE are unclear. This case study helps to elucidate the histopathological risk factors of metastasis in CASTLE.
DISCUSSION: We found that prominent lymphovascular invasion and higher proliferative activities might be risk factors of metastasis in CASTLE. In addition, we have summarised the cytological, morphological, and immunohistochemical features of CASTLE for an accurate diagnosis.
METHODS: On 24 July 2020, 13 dermatologists from 10 countries (Brazil, Canada, China, Egypt, France, Germany, Japan, Malaysia, the UK and the USA) attended a workshop to share experiences in managing patients with GPP. Educational needs and clinical practice gaps grouped according to healthcare system level were discussed and ranked using interactive polling.
RESULTS: Lack of experience of GPP among HCPs was identified as an important individual HCP-level clinical practice gap. Limited understanding of the presentation and pathogenesis of GPP among non-specialists means misdiagnosis is common, delaying referral and treatment. In countries where patients may present to general practitioners or emergency department HCPs, GPP is often mistaken for an infection. Among dermatologists who can accurately diagnose GPP, limited knowledge of treatments may necessitate referral to a colleague with more experience in GPP. At the organisational level, important needs identified were educating emergency department HCPs to recognise GPP as an autoinflammatory disease and improving communication, cooperation and definitions of roles within multidisciplinary teams supporting patients with GPP. At the regulatory level, robust clinical trial data, clear and consistent treatment guidelines and approved therapies were identified as high priorities.
CONCLUSIONS: The educational imperative most consistently identified across the participating countries is for HCPs to understand that GPP can be life-threatening if appropriate treatment initiation is delayed, and to recognise when to refer patients to a colleague with more experience of GPP management.
OBJECTIVE: To develop an international consensus definition and diagnostic criteria for GPP using the modified Delphi method.
EVIDENCE REVIEW: The rarity of GPP presents a challenge in acquiring comprehensive published clinical data necessary for developing standardized definition and criteria. Instead of relying on a literature search, 43 statements that comprehensively addressed the fundamental aspects of the definitions and diagnostic criteria for GPP were formulated based on expert reviews of 64 challenging GPP cases. These statements were presented to a panel of 33 global GPP experts for voting, discussion, and refinements in 2 virtual consensus meetings. Consensus during voting was defined as at least 80% agreement; the definition and diagnostic criteria were accepted by all panelists after voting and in-depth discussion.
FINDINGS: In the first and second modified Delphi round, 30 (91%) and 25 (76%) experts participated. In the initial Delphi round, consensus was achieved for 53% of the statements, leading to the approval of 23 statements that were utilized to develop the proposed definitions and diagnostic criteria for GPP. During the second Delphi round, the final definition established was, "Generalized Pustular Psoriasis is a systemic inflammatory disease characterized by cutaneous erythema and macroscopically visible sterile pustules." It can occur with or without systemic symptoms, other psoriasis types, and laboratory abnormalities. GPP may manifest as an acute form with widespread pustules or a subacute variant with an annular phenotype. The identified essential criterion was, "Macroscopically visible sterile pustules on erythematous base and not restricted to the acral region or within psoriatic plaques."
CONCLUSIONS AND RELEVANCE: The achievement of international consensus on the definition and diagnostic criteria for GPP underscores the importance of collaboration, innovative methodology, and expert engagement to address rare diseases. Although further validation is needed, these criteria can serve as a reference point for clinicians, researchers, and patients, which may contribute to more accurate diagnosis and improved management of GPP.