Dermatopathology, Volume 9, Issue 4 (December 2022) – 10 articles

Cystic neutrophilic granulomatous mastitis is a rarely reported, benign, mastitis that is not associated with lactation. The pathophysiology is still unknown; however, there is often a relationship with Corynebacterium kroppenstedtii. Cystic neutrophilic mastitis can have deep seated tender nodules and cutaneous ulceration which can clinically resemble pyoderma gangrenous. It can be treatment refractory and can progress to a point where mastectomy is required. This case series reports two patients treated with adalimumab with remission of disease. One patient first received dapsone with remission of symptoms, but incompatible side effects resulted in discontinuation. Both dapsone and adalimumab appear to provide disease remission in patients with cystic neutrophilic granulomatous mastitis. Full article

Introduction: Cutaneous metastases represent 2% of skin tumors, with an overall incidence of 5.3%. Although rare, clinical presentations of cutaneous metastasis vary and can be mistaken for benign and malignant skin conditions. Methodology: This was a descriptive, retrospective review of all patients diagnosed with cutaneous metastasis seen at the Department of Dermatology from January 2013 to December 2019. Clinical and histopathologic data from the patients were collated from medical records, and slides were retrieved for review. Results: A total of 115 patients were included and 122 slides reviewed. There were more female than males, the mean age was 52.3 ± 14.0 years of age. The most common primary cancer was the breast, and accordingly, the most common location was anterior chest. Among the 122 slides reviewed from 104 patients, the most common histologic type was adenocarcinoma (72.1%), and showed the infiltrative pattern (26.2%). Other histologic types seen were melanoma (13.1%), leukemic infiltrates (11.5%), squamous origin (2.5%), and epithelioid sarcoma (0.8%). Lymphovascular invasion and dermal sclerosis were observed. Immunohistochemical stains were performed in only 13.9% of the cases. There was a high concurrence of the clinical with the histopathologic diagnosis (95.6%). Conclusion: Although rare, patients with cutaneous metastasis may present in dermatology clinics. Knowledge of clinical features and low threshold for doing biopsies may prove useful for these patients. Similarly, dermatopathologists should be able to recognize histologic features of cutaneous metastasis morphologically. Histologic features may be subtle and may be reminiscent of benign inflammatory conditions, hence judicious use of immunohistochemical staining is recommended. Full article

Dupilumab is a humanized IgG4 monoclonal-antibody that is approved by the United States Food and Drug Administration (FDA) for the treatment of moderate-to-severe atopic dermatitis (AD) in patients aged 12 years and older. In recent years, several case studies have associated the unmasking or progression of cutaneous T-cell lymphomas (CTCL) with dupilumab treatment. To date, all reported cases of dupilumab-associated CTCL have shown a CD4+ T-helper-cell-predominant immunophenotype. Here, we report a case of a 72-year-old man who presented with a 2-year history of a diffuse, pruritic eruption, who was started on dupilumab for 9 weeks. He subsequently developed mycosis fungoides (MF) with a CD8+-predominant immunophenotype. Overall, cases of CD8+ mycosis fungoides are less common and relatively less understood than their CD4+ counterparts, with varied presentations and courses. We present a case of dupilumab-associated CD8+ MF to highlight this presentation for pathologists and providers. Full article

Dermatofibrosarcoma protuberans (DFSP) is a rare, locally aggressive spindle cell mesenchymal tumor arising in the dermis, with low metastatic potential. The most commonly affected sites are the trunk and proximal extremities; rarely are acral sites involved. Atrophic DFSP is a rare form of DFSP, that is morphologically different but histologically similar to DFSP. It commonly affects young adults between the ages of 20 to 50 years. The current management strategy for atrophic DFSP is surgical excision with long-term follow-up to detect any recurrence. Only one known case of atrophic DFSP with eosinophilic infiltration is what makes our case an exceptionally rare presentation. Full article

The year 2022 will herald approximately 100,000 new cases of cutaneous melanoma (CM), and over 7000 deaths from CM. Over the past 40 years, CM incidence has increased nearly six-fold; however, annual mortality has remained relatively constant. These trends encapsulate the phenomenon of overdiagnosis. Increased recognition of indolent lesions that appear histologically malignant may be leading to a melanoma epidemic. Enhanced melanoma awareness, screening efforts, physician uncertainty, medical-legal pressures, and diagnostic scrutiny using tools like immunohistochemical staining, mole mapping, dermoscopy, confocal microscopy, and molecular diagnostics contribute to increased CM diagnosis. As a result, current melanoma staging and treatment guidelines are being challenged. Existing standards fail to accurately identify histologically benign lesions that are lethal or, conversely, histologically malignant lesions that are innocuous. Healthcare systems and, more importantly, patients suffer from this diagnostic ambiguity that leads to the over-treatment of innocuous melanomas and under-treatment of aggressive melanomas. As dermatology continues to experience a shift towards earlier diagnosis of melanoma, management strategies must adapt. Herein, we review factors that may contribute to the increased incidence of melanoma, emphasize deficiencies in current staging systems, and provide insights into the future of melanoma management via precision medicine. Full article

Blue nevus is a benign melanocytic lesion, typically asymptomatic and of unknown etiology. Several histologic and clinical variants have been distinguished, the most frequent being common blue nevus, cellular blue nevus, and combined blue nevus. Although melanocytic nevi with a satellite lesion are usually suggestive of locally advanced malignant melanoma, very few cases of blue nevi with satellite lesions have been reported. The diagnosis of common or cellular blue nevi is generally straightforward; however, the presence of structures such as irregular edges or satellitosis are highly suggestive for malignancy, and differential diagnoses such as locally advanced malignant melanoma and malignant blue nevus should be considered. Recurrent blue nevi can display atypical features not seen in the primary lesion, such as pleomorphism and mitotic activity. They usually tend to follow a benign course; however, in some cases, recurrence may indicate malignant transformation. We here report the unique case of a 64-year-old woman with a recurrent cellular blue nevus accompanied by satellite lesions. Such a biological behavior resulting in a clinical presentation as a melanoma-like lesion is a rarity in blue nevus and has not been described before. Full article

Clear cell acanthoma (CCA) is classically considered a benign epidermal tumor, although rare case reports have described CCA with malignant features. Here, we present a case of a patient with a biopsy proven CCA that regrew post-biopsy and was subsequently completely excised. Histologic examination of the tumor in the excision specimen revealed malignant cytologic features that were not present in the initial biopsy. A review of the literature identified five additional cases of CCA with similar malignant cytologic features. On analysis, common histopathologic characteristics included cellular pleomorphism, increased nuclear-to-cytoplasmic ratio, prominent nucleoli, and atypical mitotic figures. We support the designation of atypical clear cell acanthoma for these entities with features of both CCA and significant cytologic atypia. As none of these cases exhibited clinically aggressive behavior, further study is warranted. Full article

Senile gluteal dermatosis (SGD) is a common but seldom recognized condition. It is characterized clinically by unilateral or bilateral hyperkeratotic, lichenified plaques on the gluteal area, being attributed to prolonged sitting, particularly in the elderly. SGD also encompasses the recently proposed entity of prurigiform angiomatosis. Histologically, there are features of lichenification, such as epidermal hyperplasia and a preserved granular layer, with prominent dermal angioproliferation. We report 4 cases of this condition as well as novel findings of variably increased mast cells and superficial lymphatic vessels in addition to the proliferation of dermal blood vessels. We propose a unifying name for Reactive Epidermal hyperplasia and Angiogenesis of the Rear (REAR) to encapsulate the characteristic clinical and histological features of this distinct entity. Full article

Skin disease remains a common complaint among deployed service members. To mitigate the limited supply of dermatologists in the U.S. Military Health System (MHS), teledermatology has been harnessed as a specialist extender platform, allowing for online consultations in remote deployed settings. Operational teledermatology has played a critical role in reductions of medical evacuations with significant cost-savings. When direct in-person lesion visualization is unattainable, teledermoscopy can be harnessed as an effective diagnostic tool to distinguish suspicious skin lesions. Teledermoscopy has the versatile capacity for streamlined incorporation into the existing asynchronous telemedicine platforms utilized worldwide among deployed U.S. military healthcare providers. In terms of clinical utility, teledermoscopy offers a unique and timely opportunity to improve diagnostic accuracy, early detection rates, and prognostic courses for dermatological conditions. Such improvements will further reduce medical evacuations and time away from mission, thereby operational improving mission readiness and combat effectiveness. As mission goals are safeguarded, associated operational budget costs are also preserved. This innovative, cost-effective technology merits integration into the U.S. Military Health System. Full article

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare tumor that affects elderly individuals and presents a poor prognosis. Skin is the most common site of involvement, accounting for 89% of the cases. Extracutaneous organs, especially bone marrow, lymph nodes, and peripheral blood, can be involved at the time of diagnosis. We report a case of BPDCN in a child, presenting with a cutaneous lesion mimicking lymphoma or leukemia cutis. The histologic findings revealed a dense diffuse infiltration by monomorphic agranular medium-sized blast cells with sparing of the grenz zone, whose first immunophenotypic profile raised the possibility of diagnosing B lymphoblastic lymphoma or leukemia. However, the absence of CD10 expression and strongly positive expression for CD4, CD56, CD45RA, and the plasmacytoid dendritic cell-associated antigens, including CD123, supported the definite diagnosis of BPDCN. The patient responded well to a systemic combination chemotherapy regimen, modified from the Associazione Italiana Ematologia Oncologia Pediatrica (AIEOP) protocol for anaplastic large cell lymphoma (ALCL), that differed from the established recommendation using ALL protocol. Owing to the patient’s excellent treatment outcome, this regimen could represent an effective alternative regimen for BPDCN in children. Full article