Incidence and Pitfalls of Adipose Tissue Encountered in Prostatic Transurethral Resections and Related Specimens.

While the presence of adipose tissue and its involvement by prostatic cancer (extraprostatic extension) is well-recognized in prostate biopsies, adipose tissue in transurethral resections of the prostate (TURP) is largely unexplored. Herein, 200 consecutive TURPs and related specimens were reviewed, including a separate 3-year analysis of specimens containing prostatic cancer, with the following data collected: presence of fat, presence of cancer within fat, and quantity of fat. For specimens with both fat and prostatic cancer, specimen weight and tumor volume were recorded. Within the 200 consecutive TURPs and related specimens, adipose tissue was identified in 20%; 55% had 2.5 mm of adipose tissue; the number of fragments with adipose tissue ranged from 1 to 14. No correlation between specimen weight and measured extent of adipose tissue or number of fragments with adipose tissue was identified. Of all the specimens with prostatic cancer, 15/56 (27%) involved adipose tissue, with two specimens with large cancer volume (>90%) demonstrating extensive involvement of adipose tissue. Adipose tissue is frequently present within TURP and related specimens with variability in extent. The etiology behind encountering adipose tissue is uncertain, and it could represent resection into peri-prostatic fat, intraprostatic fat, or bladder neck fat sampling. Although encountering adipose tissue involved by cancer in TURP and related specimens may imply extraprostatic extension (pT3a), further studies are needed to corroborate these findings as well as to determine if these should be included in reported synoptics.

When is lethal deceptive pollination maintained? A population dynamics approach.

BACKGROUND AND AIMS: Not all plant-pollinator interactions are mutualistic, and in fact, deceptive pollination systems are widespread in nature. The genus Arisaema has a pollination system known as lethal deceptive pollination, in which plants not only attract pollinating insects without providing any rewards, but also trap them until they die. Many Arisaema species are endangered from various disturbances including reduction in forest habitat, modification of the forest understory owing to increasing deer abundance, and plant theft for horticultural cultivation. We aimed to theoretically investigate how lethal deceptive pollination can be maintained from a demographic perspective and how plant and pollinator populations respond to different types of disturbance. METHODS: We developed and analysed a mathematical model to describe the population dynamics of a deceptive plant species and its victim pollinator. Calibrating the model based on empirical data, we assessed the conditions under which plants and pollinators could coexist, while manipulating relevant key parameters. KEY RESULTS: The model exhibited qualitatively distinct behaviours depending on certain parameters. The plant becomes extinct when it has a low capability for vegetative reproduction and slow transition from male to female, and plant-insect co-extinction occurs especially when the plant is highly attractive to male insects. Increasing deer abundance has both positive and negative effects because of removal of other competitive plants and diminishing pollinators, respectively. Theft for horticultural cultivation can readily threaten plants whether male or female plants are frequently collected. The impact of forest habitat reduction may be limited compared to that of other disturbance types. CONCLUSIONS: Our results have emphasised that the demographic vulnerability of lethal deceptive pollination systems would differ qualitatively from that of general mutualistic pollination systems. It is therefore important to consider the demographics of both victim pollinators and deceptive plants to estimate how endangered Arisaema populations respond to various disturbances.

Establishing Silphids in the invertebrate DNA toolbox: a proof of concept.

Environmental DNA (eDNA) analyses are an increasingly popular tool for assessing biodiversity. eDNA sampling that uses invertebrates, or invertebrate DNA (iDNA), has become a more common method in mammal biodiversity studies where biodiversity is assessed via diet analysis of different coprophagous or hematophagous invertebrates. The carrion feeding family of beetles (Silphidae: Coleoptera, Latreille (1807)), have not yet been established as a viable iDNA source in primary scientific literature, yet could be useful indicators for tracking biodiversity in forested ecosystems. Silphids find carcasses of varying size for both food and reproduction, with some species having host preference for small mammals; therefore, iDNA Silphid studies could potentially target small mammal communities. To establish the first valid use of iDNA methods to detect Silphid diets, we conducted a study with the objective of testing the validity of iDNA methods applied to Silphids using both Sanger sequencing and high throughput Illumina sequencing. Beetles were collected using inexpensive pitfall traps in Alberta, Michigan in 2019 and 2022. We successfully sequenced diet DNA and environmental DNA from externally swabbed Silphid samples and diet DNA from gut dissections, confirming their potential as an iDNA tool in mammalian studies. Our results demonstrate the usefulness of Silphids for iDNA research where we detected species from the genera Anaxyrus, Blarina, Procyon, Condylura, Peromyscus, Canis, and Bos. Our results highlight the potential for Silphid iDNA to be used in future wildlife surveys.

Comparison of Primary and Metastatic Fumarate Hydratase-Deficient Renal Cell Carcinomas Documents Morphologic Divergence and Potential Diagnostic Pitfall With Peritoneal Mesothelioma.

Fumarate hydratase (FH)-deficient renal cell carcinomas are rare neoplasms characterized by wide morphologic heterogeneity and pathogenetic mutations in the FH gene. They often show aggressive behavior with rapid diffusion to distant organs, so novel therapeutic scenarios have been explored, including EGFR inhibitors and PD-L1 expression for targeted immunotherapy. Herein, we investigated a series of 11 primary FH-deficient renal cell carcinomas and 7 distant metastases to evaluate tumor heterogeneity even in metastatic sites and estimate the specific spread rates to various organs. Furthermore, the tumors were tested for immunohistochemical PD-L1 expression and EGFR mutations. Most metastatic cases involved the abdominal lymph nodes (4/7; 57%), followed by the peritoneum (3/7; 42%), the liver (2/7; 29%), and the lungs (1/7; 14%). Six metastatic localizations were histologically documented, revealing a morphologic heterogeneous architecture often differing from that of the corresponding primary renal tumor. Peritoneal involvement morphologically resembled a benign reactive mesothelial process or primary peritoneal mesothelioma, thus advocating to perform an accurate immunohistochemical panel, including PAX8 and FH, to reach a proper diagnosis. A pure low-grade succinate dehydrogenase-looking primary FH-deficient renal cell carcinoma was also recorded. As for therapy, significant PD-L1 labeling was found in 60% of primary renal tumors, whereas none of them carried pathogenetic EGFR mutations. Our data show that FH-deficient renal cell carcinoma may be morphologically heterogeneous in metastases as well, which involve the lymph nodes, the liver, and the peritoneum more frequently than other renal tumors. Due to the high frequency of this latter (42%), pathologists should always be concerned about ruling out mesothelial-derived mimickers, and the occurrence of rarer, primary, low-grade-looking types. Finally, contrary to EGFR mutations, PD-L1 expression could be a possible predictive biomarker for the therapy of these tumors.

Persistent Buccal Ulcer with Underlying Non-Neoplastic Ectopic Lymphoid Aggregates: A Tonsillar Tissue?

We presented a case of a 46-year-old woman from Saudi Arabia with a persistent buccal ulcer, measuring 0.4 × 0.4 × 0.3 cm. After surgical excision of the lesion was performed using both general and local anesthesia, its microscopic examination revealed keratinized squamous epithelium with surface ulcerations in the buccal mucosa. Beneath the epithelium, there was granulation tissue, scattered and clustered lymphoid tissue, and reactive germinal centers with tingible body microphages. These lymphoid clusters infiltrated the adjacent skeletal muscles and fat. The final diagnosis was ectopic oral tonsillar tissue overlaid by an inflammatory ulcer, most likely attributed to friction. Importantly, no evidence of malignancy were observed in the biopsy. The surgical removal of the lesion was performed to rule out malignancy. The surgical excision was performed using both general and local anesthesia. Following surgery and during follow-up visits, the indicated instructions were provided. Pain was effectively managed with acetaminophen, and the patient fully recovered in approximately ten days. Neither recurrence nor post-operative complications were hitherto reported. Supplementary Information: The online version contains supplementary material available at 10.1007/s12070-024-04536-8.

Mismatch between Augmented Reality Navigation Images and Actual Location of a Cauda Equina Tumor:A Case Report.

BACKGROUND: Augmented reality navigation is the one of the navigation technologies that allows computer-generated virtual images to be projected onto a real-world environment. Augmented reality navigation can be used in spinal tumor surgery. However, it is unknown if there are any pitfalls when using this technique. CASE PRESENTATION: The patient in this report underwent complete resection of a cauda equina tumor at the L2-L3 level using microscope-based augmented reality navigation. Although the registration error of navigation was <1 mm, we found a discrepancy between the augmented reality navigation images and the actual location of the tumor, which we have called "navigation mismatch". This mismatch, which was caused by the mobility of the spinal tumor in the dura mater, seems to be one of the pitfalls of augmented reality navigation for spinal tumors. CONCLUSIONS: Combined use of intraoperative ultrasound and augmented reality navigation seems advisable in such cases. J. Med. Invest. 71 : 174-176, February, 2024.

FAPI PET uptake patterns after invasive medical interventions: a single center retrospective analysis.

PURPOSE: Fibroblast activation protein (FAP)-inhibitor (FAPI)-PET tracers allow imaging of the FAP-expressing cancer associated fibroblasts (CAF) and also the normal activated fibroblasts (NAF) involved in inflammation/fibrosis that may be present after invasive medical interventions. We evaluated [68Ga]Ga-FAPI-46 uptake patterns post-medical/invasive non-systemic interventions. METHODS: This single-center retrospective analysis was conducted in 79 consecutive patients who underwent [68Ga]Ga-FAPI-46 PET/CT. Investigators reviewed prior patient medical/invasive interventions (surgery, endoscopy, biopsy, radiotherapy, foreign body placement (FBP) defined as implanted medical/surgical material present at time of scan) and characterized the anatomically corresponding FAPI uptake intensity both visually (positive if above surrounding background) and quantitatively (SUVmax). Interventions with missing data/images or confounders of [68Ga]Ga-FAPI-46 uptake (partial volume effect, other cause of increased uptake) were excluded. Available correlative FDG, DOTATATE and PSMA PET/CTs were analyzed when available. RESULTS: 163 medical/invasive interventions (mostly surgeries (49%), endoscopies (18%) and non-surgical biopsies (10%)) in 60 subjects were included for analysis. 43/163 (26%) involved FBP. FAPI uptake occurred in 24/163 (15%) of interventions (average SUVmax 3.2 (mild), range 1.5-5.1). The median time-interval post-intervention to FAPI-PET was 47.5 months and was shorter when FAPI uptake was present (median 9.5 months) than when absent (median 60.1 months; p = 0.001). Cut-off time beyond which no FAPI uptake would be present post-intervention without FBP was 8.2 months, with a sensitivity, specificity, positive predictive value and negative predictive value of 82, 90, 99 and 31% respectively. No optimal cutoff point could be determined when considering interventions with FBP. No significant difference was detected between frequency of [68Ga]Ga-FAPI-46 and [18F]FDG uptake in intervention sites. Compared to [68Ga]Ga-PSMA-11, [68Ga]Ga-FAPI-46 revealed more frequent and intense post-interventional tracer uptake. CONCLUSION: [68Ga]Ga-FAPI-46 uptake from medical/invasive interventions without FBP appears to be time dependent, nearly always absent beyond 8 months post-intervention, but frequently present for years with FBP.

Gastric Signet Ring Cell Carcinoma Metastasis From Lobular Breast Cancer: A Diagnostic Pitfall.

Breast cancer is the most common type of cancer among women worldwide. Gastric metastasis from invasive lobular carcinoma of the breast is unusual. We report the case of a 66-year-old woman, under follow-up for an invasive classic lobular carcinoma of the left breast treated four years prior, who was admitted for upper abdominal discomfort and worsening constipation. Linitis plastica was suspected at gastroscopy. Histology of gastric biopsies showed a poorly cohesive carcinoma comprising signet ring cells, with no resemblance to the original breast cancer. An adequate immunochemistry panel, including estrogen receptor and GATA-3, eliminated primary gastric cancer and proved that the gastric lesion was a metastasis of the previously diagnosed invasive lobular breast cancer with additional signet ring cell differentiation, which is classified among its rare variants. This challenging case shows the importance of oncologic medical history and immunochemistry in differentiating between metastasis from invasive lobular breast carcinoma and primary gastric cancer. The distinction is necessary as the prognosis and approaches for treatment are different. When encountering a gastric signet ring cell carcinoma, one must keep in mind that it actually can be a metastasis from one of the several primary sites of origin.

Metastatic triple-negative breast carcinoma mimicking melanoma: A potential diagnostic pitfall.

Melanoma, with its diverse histopathologic characteristics, can mimic both benign nevi and neoplasms of various cell lineages. Immunohistochemistry (IHC) can play a vital role in melanoma diagnosis, particularly when the cell lineage is unclear on hematoxylin and eosin sections. Commonly utilized IHC stains for melanoma diagnosis include SOX10, Melan-A, and S100. A relatively novel stain, PReferentially expressed Antigen in MElanoma (PRAME), is also proving useful in accurate melanoma diagnosis. However, none of these stains are completely specific to melanocytes or melanoma, and misinterpretation can lead to incorrect diagnoses. This report presents a unique case of triple-negative breast carcinoma (TNBC) metastatic to the skin exhibiting histopathologic characteristics similar to melanoma, including positivity for SOX10 and PRAME. Our aim is to highlight TNBC metastatic to the skin as a potential diagnostic pitfall.

Distinct communities under the snow: describing characteristics of subnivium arthropod communities.

Arthropods are active during the winter in temperate regions. Many use the seasonal snowpack as a buffer against harsh ambient conditions and are active in a refugium known as the subnivium. While the use of the subnivium by arthropods is well established, far less is known about subnivium community composition, abundance, biomass, and diversity and how these characteristics compare with the community in the summer. Understanding subnivium communities is especially important given the observed and anticipated changes in snowpack depth and duration due to the changing climate. We compared subnivium arthropod communities with those active during the summer using pitfall trapping in northern New Hampshire. We found that compositions of ground-active arthropod communities in the subnivium differed from those in the summer. The subnivium arthropod community featured moderate levels of richness and other measures of diversity that tended to be lower than the summer community. More strikingly, the subnivium community was much lower in overall abundance and biomass. Interestingly, some arthropods were dominant in the subnivium but either rare or absent in summer collections. These putative "subnivium specialists" included the spider Cicurina brevis (Emerton 1890) (Araneae: Hahniidae) and 3 rove beetles (Coleoptera: Staphylinidae): Arpedium cribratum Fauvel, 1878, Lesteva pallipes LeConte, 1863, and Porrhodites inflatus (Hatch, 1957). This study provides a detailed account of the subnivium arthropod community, establishes baseline information on arthropod communities in temperate forests of northeastern North America, and explores the idea of subnivium specialist taxa that are highly active in winter and might be especially vulnerable to climate change.

Intense prostate-specific membrane antigen receptor expression in coronary artery pypass graft scar tissue: A potential molecular imaging pitfall.

68Gallium-PSMA positron emission tomography/computer tomography has been utilized recently for the diagnosis and staging of prostate cancer. PSMA is a transmembrane protein that is expressed not only in the prostate gland but also in other tissues. While some pitfalls have been addressed, there are still uncertainties. Herein, we report a 79-year-old male with prostate cancer who underwent a PSMA scan after coronary artery bypass graft surgery, revealing disease progression and PSMA-avid foci at the surgical stitch sites. This report discusses the immunohistochemical and molecular imaging mechanisms underlying PSMA expression in surgical scar tissues, providing critical insights for optimizing radiologic reporting in such situations.

Abnormal expression of LCA and CD43 in SCLC: a rare case report and brief literature review.

BACKGROUND: To present an unusual case of abnormal LCA expression and CD43 in SCLC and to review the reported literature to avoid potential diagnostic pitfalls. CASE PRESENTATION: A 73-year-old male patient suffered from persistent back pain for more than one month. MRI revealed a compression fracture of the L1-L5 vertebra. A CT scan revealed multiple nodules and masses at the left root of the neck, lung hilum and mediastinum, and multiple areas of bony destruction of the ribs. Histology of the tumor revealed that small and round cells were arranged in nests with areas of necrosis. The tumor cells were round to ovoid with scant cytoplasm and indistinct cell borders. The nuclear chromatin was finely granular, and the nucleoli were absent or inconspicuous. Immunohistochemically, the tumor cells were positive for cytokeratin, TTF-1, POU2F3, LCA, and CD43. CONCLUSION: This report highlights a potential diagnostic pitfall in the diagnosis of SCLC, urges pathologists to exercise caution in cases of LCA and CD43 positivity and illustrates the need for further immunohistochemical studies to avoid misdiagnosis.

GATA3 Expression in Prostatic Adenosquamous Carcinoma: A Potential Diagnostic Pitfall.

Urothelial carcinoma and prostatic adenocarcinoma can have overlapping histologic features and in some instances pose challenges to pathologists. GATA binding protein 3 (GATA3) immunohistochemistry (IHC) is a well-established tool to aid in this specific diagnostic dilemma as it has been shown to be a sensitive marker for urothelial carcinoma and a putatively specific marker in excluding prostatic adenocarcinoma. However, in encountering an index tumor of prostatic adenosquamous carcinoma positive for GATA3, herein we sought to investigate this potential diagnostic pitfall in a larger series of tumors. In this study, we retrospectively reviewed prostatic adenosquamous carcinomas diagnosed in 17 patients across the authors' institutions and personal consult collections in the past 10 years. GATA3 IHC was either reviewed or performed on tumors not previously tested. We also recorded other immunostains that were performed at initial diagnosis. Positivity for GATA3 was found in 9 of 17 (53%) tumors, all within squamous regions (2 tumors also showed concomitant moderate GATA3 positivity within glandular elements). The GATA3 positive tumors were all positive for p63 in the 7 tumors where p63 was also performed. Of all tumors tested, NKX3.1 was positive in 100% (13/13) of the glandular elements (3 tumors also showed NKX3.1 concomitant positivity within squamous regions). In summary, when encountering a carcinoma with mixed glandular/squamous features in which prostatic origin is being considered, awareness of GATA3 immunoreactivity in a subset of prostatic adenosquamous carcinoma is critical to avoid diagnostic pitfalls.

Mind the Pitfall: Solitary Nodular Fasciitis Mimicking Extra-Nodal Manifestation of Hodgkin Lymphoma on [18F]FDG PET/CT.

We report a [18F]fluorodeoxyglucose positron emission tomography/computed tomography ([18F]FDG PET/CT) scan of a 17-year-old male presenting increased focal glucose metabolism of a histologically proven solitary nodular fasciitis mimicking an extranodal manifestation of Hodgkin lymphoma. This interesting image should draw attention to considering nodular fasciitis as a possible pitfall in the staging of malignant diseases.

Fracture or Not: An Easily Mistaken Benign Finding in a Tuberous Sclerosis Patient.

Tuberous sclerosis (TSC) is a rare autosomal dominant disorder that can affect multiple organ systems, including the brain, heart, lungs, and skin. Cutaneous manifestations are common, including ungual fibromas, however, these may be mistaken for other pathologies. Here, we present the case of a 14-year-old with TSC complaining of traumatic left little finger pain. Radiographic evaluation revealed cortical scalloping of the nailbed, concerning for a non-displaced fracture. Given the history of TSC, however, this defect may have also represented a periungual fibroma. The patient subsequently underwent conservative management and an eight-month radiographic follow-up showed no osseous remodeling, supporting the diagnosis of periungual fibroma. It is imperative for clinicians to understand the cutaneous manifestations of TSC to aid in proper diagnosis and avoidance of unnecessary treatment. In this case, interval follow-up confirmed the diagnosis and excluded fracture.

Low-Powered View, High-Powered Mind: A Case Report of Morpheaform Basal Cell Carcinoma Mistaken for Metastatic Breast Carcinoma.

Basal cell carcinoma (BCC) is one of the most common skin malignancies worldwide. Morpheaform basal cell carcinoma (MBCC) is a rare aggressive subtype of BCC that presents with unique histologic features. Both are treated surgically and have an excellent survival rate. Metastatic breast carcinoma, on the other hand, has a poor survival rate along with a more burdensome therapeutic route including chemotherapy. Due to an overlap in common immunohistochemistry stains, there is a possibility of confusing the diagnosis of BCC with metastatic breast carcinoma resulting in potential patient harm. Therefore, a timely and accurate diagnosis distinguishing these malignancies is essential. We report a near-miss event in which a 77-year-old female with MBCC was mistakenly diagnosed with metastatic breast carcinoma. We discuss the details of these stains, characteristic features of MBCC, and treatment options and emphasize the importance of combining laboratory medicine with clinical expertise to improve patient outcomes.

Capacity and establishment rules govern the number of nonnative species in communities of ground-dwelling invertebrates.

Nonnative species are a key agent of global change. However, nonnative invertebrates remain understudied at the community scales where they are most likely to drive local extirpations. We use the North American NEON pitfall trapping network to document the number of nonnative species from 51 invertebrate communities, testing four classes of drivers. We sequenced samples using the eDNA from the sample's storage ethanol. We used AICc informed regression to evaluate how native species richness, productivity, habitat, temperature, and human population density and vehicular traffic account for continent-wide variation in the number of nonnative species in a local community. The percentage of nonnatives varied 3-fold among habitat types and over 10-fold (0%-14%) overall. We found evidence for two types of constraints on nonnative diversity. Consistent with Capacity rules (i.e., how the number of niches and individuals reflect the number of species an ecosystem can support) nonnatives increased with existing native species richness and ecosystem productivity. Consistent with Establishment Rules (i.e., how the dispersal rate of nonnative propagules and the number of open sites limits nonnative species richness) nonnatives increased with automobile traffic-a measure of human-generated propagule pressure-and were twice as common in pastures than native grasslands. After accounting for drivers associated with a community's ability to support native species (native species richness and productivity), nonnatives are more common in communities that are regularly seasonally disturbed (pastures and, potentially deciduous forests) and those experiencing more vehicular traffic. These baseline values across the US North America will allow NEON's monitoring mission to document how anthropogenic change-from disturbance to propagule transport, from temperature to trends in local extinction-further shape biotic homogenization.

How Can the Clinical Aptitude of AI Assistants Be Assayed?

Large language models (LLMs) are exhibiting remarkable performance in clinical contexts, with exemplar results ranging from expert-level attainment in medical examination questions to superior accuracy and relevance when responding to patient queries compared to real doctors replying to queries on social media. The deployment of LLMs in conventional health care settings is yet to be reported, and there remains an open question as to what evidence should be required before such deployment is warranted. Early validation studies use unvalidated surrogate variables to represent clinical aptitude, and it may be necessary to conduct prospective randomized controlled trials to justify the use of an LLM for clinical advice or assistance, as potential pitfalls and pain points cannot be exhaustively predicted. This viewpoint states that as LLMs continue to revolutionize the field, there is an opportunity to improve the rigor of artificial intelligence (AI) research to reward innovation, conferring real benefits to real patients.

Recognizing puzzling PD1 + infiltrates in marginal zone lymphoma by integrating clonal and mutational findings: pitfalls in both nodal and transformed splenic cases.

BACKGROUND: A marked increase in PD1-positive TFH cells in nodal MZL cases (NMZL) was reported previously and could prompt suspicion for a diagnosis of peripheral T-cell lymphoma (PTCL), especially angioimmunoblastic T-cell lymphoma (AITL). CASE PRESENTATION: To demonstrate that the pitfall might exist not only in NMZL but also in transformed splenic MZL (tSMZL), two NMZL cases (70 y/o female with enlarged left cervical lymph node and 75 y/o male with generalized lymphadenopathy) and one case of tSMZL (47 y/o male with nodal and extranodal involvement) with obvious PD1-positive T-cell hyperplasia were described here. Although all their initial diagnoses were prompted to be AITL, they were comprehensively characterized by clinical features, morphologic, immunophenotypic, clonality, and targeted exosome sequencing (TES) findings. Case 1 and Case 2 were NMZL with increased PD1 + T cells in the "peripheral pattern" or "mixed peripheral and central pattern", and Case 3 was SMZL with abundant PD1-positive T cells in the "nodular pattern" that transformed to tSMZL (DLBCL) with PD1-positive T cells distributed in the "diffuse pattern." In addition to the monoclonal IG rearrangement and polyclonal TCR rearrangement results, TES demonstrated enriched and recurrent mutations in MZLs and failed to find aberrations described in AITL- or TFH-derived lymphomas. CONCLUSIONS: It is important to realize that this pitfall can also occur in more diagnostically difficult tSMZL cases; the integration of histopathology with clonality and mutation studies is also highlighted.

Dermatomyositis with Eosinophils.

Dermatomyositis is an idiopathic inflammatory myopathy that often presents with symmetric proximal skeletal muscle weakness and characteristic skin findings. Typical skin biopsy findings include vacuolar changes of the basal layer, increased dermal mucin, and a predominantly lymphocytic infiltrate. We report a case of dermatomyositis presenting as intensely pruritic papules and plaques, with initial histopathology being atypical of dermatomyositis due to the presence of eosinophils. The initial biopsy demonstrated a superficial dermatitis with eosinophils, initially thought to represent a drug eruption. A second biopsy of the same cutaneous manifestation was performed at a later time given high clinical suspicion for dermatomyositis and demonstrated a more classic vacuolar interface dermatitis with increased mucin and an absence of eosinophils. Notably, increased pruritus was specifically associated with the lesion that demonstrated tissue eosinophilia. The case illustrates the importance of considering tissue eosinophilia in the histologic presentation of dermatomyositis.