Neurofibroma with glomus-like bodies: A novel association-Thoughts about origin

A neurofibroma with focal glomus-like body differentiation is an unusual phenomenon recently encountered in an excision specimen from the right lateral distal forearm of a 26-year-old man. Glomus cells are modified smooth muscle cells normally present in glomus-like bodies but can also be found in glomus tumors (GT) or lesions considered in the spectrum of GT, including myopericytoma, myofibroma, and angiolipoma. Neurofibromas are peripheral nerve sheath tumors derived from the neural crest cells. While both GT and its variants and neurofibroma are thought to be derived from different cell types, there is growing evidence that glomus cells have a neural crest origin. This is based on multiple theories, with some overlapping pathways, including neural crest cell differentiation, Schwann cell reprogramming, VEGF expression, and NF1 gene biallelic inactivation. This report adds to the growing evidence of possible neural crest origin for glomus cells and would help explain finding glomus-like bodies scattered through a neurofibroma.

Chronic Radiation Dermatitis Secondary to Narrow-Band Ultraviolet B Therapy in a Patient With Primary Cutaneous CD8 + T-Cell Lymphoma With Cytotoxic Granules

ABSTRACT

Conventional therapies for CD8 + cutaneous T-cell lymphoma include topical steroids, topical nitrogen mustard, topical bexarotene, ultraviolet B therapy, psoralen and ultraviolet A therapy, local radiotherapy, and interferon alfa; however, these treatments are often found to be ineffective. Presented is a case of CD8 + cutaneous T-cell lymphoma with near-complete response to narrow-band ultraviolet therapy because of chronic radiation dermatitis initially believed to be possible progression of a CD8 + cutaneous epidermotropic cytotoxic T-cell lymphoma.

BerEP4-Negative Basal Cell Carcinoma: An Immunophenotype Not to Forget

ABSTRACT

Basal cell carcinoma (BCC) is the most common cancer worldwide. Although not typically metastatic, BCC can be locally destructive. BerEP4 is an antibody against CD326, an epithelial cell adhesion molecule (EpCAM) that is expressed on epithelial progenitor cells and carcinomas. BerEP4 has been reported to have a 100% positive sensitivity in basal cell carcinomas, but a much lower sensitivity for a variety of other carcinomas, including clear cell renal cell carcinoma and metastatic renal cell carcinoma. A 74-year-old woman presented with a BerEP4-negative, but anti-renal cell antibody-positive BCC, and the stark clinical implications of misdiagnosis. This case stresses the importance of considering BerEP4-negative BCC, even when other abnormal features are present.

Lenalidomide-induced symmetrical drug-related intertriginous and flexural exanthema

Symmetric drug-related intertriginous and flexural exanthema (SDRIFE) is a cutaneous drug reaction that presents with symmetrical erythema in the flexures. The reaction typically appears hours-to-days after drug exposure but has been reported to occur months after drug initiation. Diagnostic criteria include cutaneous reaction after exposure to a systemic drug, erythema of the gluteal region and/or V-shaped erythema of the inguinal areas, involvement of an additional intertriginous site, symmetry, and absence of systemic involvement. The rash typically presents as macular erythema. However, variations in morphology have been reported including papules, pustules, vesicles, and bullae. The histopathology of SDRIFE is non-specific and the diagnosis is made clinically. Cessation of the causative drug leads to gradual rash resolution. Beta-lactam antibiotics are the most implicated medications but case reports describe SDRIFE following monoclonal antibodies, chemotherapeutic agents, and various other medications. We present a patient with SDRIFE secondary to lenalidomide, an immunomodulatory agent. This case highlights the importance of considering SDRIFE in the differential diagnosis of patients presenting with intertriginous erythema.

Radiation-Induced Eccrine Squamous Syringometaplasia With Perineural Invasion

ABSTRACT

Eccrine squamous syringometaplasia (ESS) is a benign metaplastic reaction of eccrine ducts that occurs in response to injury and can be a histologic mimic of squamous cell carcinoma (SCC). Reported is an 82-year-old man undergoing Mohs surgery for presumed SCC diagnosed in a field of radiation dermatitis. After 3 Mohs stages, the peculiar squamous proliferation was recognized as ESS and the procedure was aborted. Complicating the interpretation of the Mohs frozen section was the presence of perineural invasion because perineural invasion has not been previously reported to occur with ESS. The histologic features used to distinguish ESS from SCC are discussed.

Pseudolymphoma to Lymphoma: A Case of Chronic Reactive Lymphoid Hyperplasia Transforming to Primary Cutaneous Marginal Zone Lymphoma

ABSTRACT

Primary cutaneous marginal zone lymphoma (PCMZL) is a low-grade malignant B-cell lymphoma that originates from the skin. It often presents as erythematous solitary or multiple papules, nodules, and/or plaques. It is one of the 3 main subtypes of primary cutaneous B-cell lymphomas. PCMZLs are believed to develop from chronic antigenic stimulation such as from tick-borne bacteria, vaccines, tattoo pigment, or other foreign body. In addition, cutaneous lymphoid hyperplasia, a documented precursor to malignant PCMZL, often presents in response to areas of chronic inflammation. Cutaneous lymphoid hyperplasia and PCMZL share several clinical and histological similarities that require clinicopathologic suspicion, immunohistochemical ancillary studies, and histopathologic analysis to accurately differentiate the 2 entities. Although gene rearrangement studies have historically been of limited value in the diagnosis of PCMZL, recent studies investigating molecular markers have identified the presence of multiple genetic abnormalities that have helped to better characterize the disease and aid in diagnosis. In addition, newer studies have found associations between PCMZL and gastrointestinal disorders, including Helicobacter pylori and inflammatory bowel disorders. In this article, we describe a case of a 56-year-old patient with a history of ulcerative colitis presenting with chronic reactive lymphoid hyperplasia that transformed to primary cutaneous marginal zone lymphoma.

Myxoid perineurioma: an entity with many mimics

We present a case of a female patient who presented with a 0.6cm flesh-colored "rubbery" papule on the left thigh. Biopsy revealed a dermal myxoid tumor containing spindled cells, tapered nuclei, indistinct cell borders, and a large number of mast cells. The spindle cells stained negative for S100 protein and Sox10 on immunohistochemistry, excluding myxoid neurofibroma, but positive for epithelial membrane antigen (EMA), and CD34, supporting a diagnosis of myxoid perineurioma. Interestingly, the mast cells showed cytoplasmic and nuclear positivity for microphthalmia transcription factor (MiTF). The lesion was fully excised one year later with identical histopathology and ancillary immunohistochemical profile.

Novel teprotumumab treatment of severe thyroid dermopathy; ototoxicity as an adverse side effect

Pretibial myxedema, more generally thyroid dermopathy, results from mucopolysaccharide accumulation in the dermis, typically between the knee and dorsal foot. Thyroid dermopathy presents in Graves disease, but can occur in Hashimoto thyroiditis, primary hypothyroidism, and euthyroid patients. Treatment of thyroid eye disease with teprotumumab is established in the literature, with few case reports also showing improvement in pretibial myxedema. Reported is a 76-year-old man with thyroid eye disease and pretibial myxedema treated with teprotumumab; improvement was demonstrated in both conditions. He developed "muffled" hearing as an adverse effect, a complication not widely published in the dermatology literature. At 18 months post-treatment, his symptoms are stable without recurrence, but hypoacusis persists. Given the long-term efficacy and side-effects, dermatologists should recognize the potential benefits and risks of using teprotumumab for thyroid dermopathy. A baseline audiogram may be considered prior to therapy. Additionally, longitudinal data is needed to document the benefits and risks of this novel therapy.

Treating linear porokeratosis with topical lovastatin/cholesterol cream

Linear porokeratosis is a rare variant of porokeratosis that is characterized by unilateral lesions along the lines of Blaschko. Like all variants of porokeratosis, linear porokeratosis is characterized by the histopathologic finding of cornoid lamellae bracketing the lesion. The underlying pathophysiology involves a two-hit post-zygotic knockdown of genes involved in mevalonate biosynthesis in embryonic keratinocytes. Although there is currently no standard or effective treatment, therapies targeted to rescue this pathway and restore keratinocyte cholesterol availability are promising. Presented here is a patient with a rare, extensive case of linear porokeratosis treated with compounded 2% lovastatin/2% cholesterol cream leading to partial resolution of the plaques.

Persistent diarrhea with petechial rash - unusual pattern of light chain amyloidosis deposition on skin and gastrointestinal biopsies: A case report

BACKGROUND

Amyloidosis is a rare disease characterized by extracellular deposition of misfolded protein aggregated into insoluble fibrils. Gastrointestinal involvement in systemic amyloidosis is common, but is often subclinical or presents as vague and nonspecific symptoms. It is rare for gastrointestinal symptoms to be the main presenting symptom in patients with systemic amyloidosis, causing it to be undiagnosed until late-stage disease.

CASE SUMMARY

A 53 year-old man with diarrhea, hematochezia, and weight loss presented to a community hospital. Colonoscopy with biopsy at that time was suspicious for Crohn disease. Due to worsening symptoms including nausea, vomiting, and a new petechial rash, an abdominal fat pad biopsy was done. The biopsy showed papillary and adnexal dermal amyloid deposition, in a pattern usually seen with cutaneous amyloidosis. However, Cytokeratin 5/6 was negative, excluding cutaneous amyloidosis. The patterns of nodular amyloidosis, subcutaneous amyloid deposits and perivascular amyloid were not seen. Periodic Acid-Schiff stain was negative for lipoid proteinosis, Congo red was positive for apple green birefringence on polarization and amyloid typing confirmed amyloid light chain amyloidosis. Repeat endoscopic biopsies of the gastrointestinal tract showed amyloid deposition from the esophagus to the rectum, in a pattern usually seen in serum amyloid A in the setting of chronic inflammatory diseases, including severe inflammatory bowel disease. Bone marrow biopsy showed kappa-restricted plasma cell neoplasm.

CONCLUSION

Described is an unusual presentation of primary systemic amyloidosis, highlighting the risk of misdiagnosis with subsequent significant organ dysfunction and high mortality.

Iatrogenic Leptomeningeal Carcinomatosis Following Craniotomy for Resection of Metastatic Serous Ovarian Carcinoma: A Systematic Literature Review and Case Report

Metastasis of ovarian carcinoma to the central nervous system occurs in <2% of cases and classically localizes within the brain parenchyma. Moreover, leptomeningeal spread of these tumors is an exceedingly rare phenomenon. Here, we conduct a systematic review of the current literature on the natural history, treatment options, and proposed pathogenic mechanisms of leptomeningeal carcinomatosis in ovarian carcinoma. We also report a case of a 67-year-old female with stage IV metastatic ovarian serous carcinoma initially confined to the peritoneal cavity with a stable disease burden over the course of three years. Follow-up imaging demonstrated an intracranial lesion, which was resected via craniotomy, and pathology was consistent with the original diagnosis. Three months after surgery, she developed rapidly progressive dizziness, generalized weakness, fatigue, and ataxia. Repeat MRI demonstrated interval development of extensive and diffusely enhancing dural nodularity, numerous avidly enhancing supratentorial and infratentorial lesions, enhancement of the bilateral trigeminal nerves, internal auditory canals, and exit wound from the surgical site into the posterior aspect of the right-sided neck musculature consistent with diffuse leptomeningeal dissemination. The present case highlights that leptomeningeal dissemination of ovarian carcinoma is a potential yet rare consequence following surgical resection of an ovarian parenchymal metastasis. Progressive clinical symptomatology that develops postoperatively in this patient population should prompt urgent workup to rule out leptomeningeal disease and an expedited radiation oncology consultation if identified.

Endometrial Cancer Characteristics and Risk of Recurrence

OBJECTIVES

To describe clinicopathologic characteristics and survival outcomes of endometrial adenocarcinomas stratified by mismatch repair (MMR) status.

METHODS

Single-institution, retrospective study of all women with endometrioid adenocarcinomas treated from January 2012 through December 2017. Patients were categorized into one of three groups based on MMR testing: intact MMR expression (MMR+), probable MMR mutation (MMR-), or MLH1 hypermethylation (hMLH1+). Demographics, pathologic characteristics, recurrence rates, and survival differences were analyzed.

RESULTS

In total, 316 women were included in the analysis: 235 (74.4%) patients in the MMR+ group, 10 (3.1%) in the MMR- group, and 71 (22.5%) in the hMLH1+ group. Patients with hMLH1+ were significantly older, exhibited higher-grade histology and presence of lymphovascular space invasion, and were more likely to have received adjuvant treatment. The early stage hMLH1+ patients were more likely to recur (15.3% hMLH1+ vs 2.3% MMR+ vs 12.5% MMR-, P < .001). Hypermethylation remained a significant predictor of recurrence in multivariable analysis (odds ratio, 5.09; 95% confidence interval [CI], 1.54-16.86; P = .008). Recurrence-free survival was significantly reduced in early stage hMLH1+ (hazard ratio, 7.40; 95% CI, 2.80-21.62; P < .001).

CONCLUSIONS

Women with hMLH1+ endometrial cancer have worse prognostic features and recur more frequently, even in patients traditionally considered low risk for recurrence.

Unusual Case of a Caruncular Oncocytoma

ABSTRACT

Oncocytomas are benign neoplasms that are most often found in the salivary glands and kidneys. Ocular oncocytoma typically present as an asymptomatic dark blue papule on the lacrimal caruncle. Histologically, the tumor is composed of oncocytes, cells notable for eosinophilic cytoplasmic granules representing large quantities of dysfunctional mitochondria. The neoplastic proliferation may be partially or totally encapsulated and may be surrounded by myoepithelial cells. Discussed is the pathophysiology and histopathology of an ocular oncocytoma from the right lacrimal caruncle of a 68-year-old man. The patient complained of a foreign body sensation and tearing associated with a purpuric 1 × 1-mm papule of the right caruncle that had been present for 6 months. An excisional biopsy showed an oxyntic neoplasm with small cystic glandular spaces associated with goblet cells and mucin, confirmed by mucicarmine stain. Given the rarity of ocular oncocytomas and presence of mucin, exclusion of an endocrine mucin-producing sweat gland carcinoma was necessary. Peripheral myoepithelial cells noted on p63 immunostaining are seen in both endocrine mucin-producing sweat gland carcinoma and oncocytomas. However, endocrine mucin-producing sweat gland carcinoma is excluded by the presence of goblet cells, the uniform oxyphilic cytoplasm of the epithelial cells, and the negative immunohistochemical staining for neuron-specific enolase, chromogranin, synaptophysin, estrogen receptor, and progesterone receptor. Complete surgical excision is the treatment of choice for oncocytomas. This case highlights the clinical and histopathological presentation of ocular oncocytomas and raises awareness of this rare entity for both the practicing dermatologist and dermatopathologist.

Kaposi sarcoma: What to do with a negative human herpesvirus 8 immunohistochemical stain?

Kaposi sarcoma (KS) is an intermediate vascular sarcoma that can cause significant morbidity and mortality in patients if left untreated. It is associated with human herpesvirus 8 (HHV-8) infection. Definitive diagnosis is supported by classic histopathology including slit-like vascular spaces, spindle cells, lymphocyte infiltration, and extravasated red blood cells on H&E stain and positive immunohistochemical (IHC) staining for HHV-8. We present a challenge we encountered in detecting HHV-8 by IHC in a mucosal lesion demonstrating classic histopathology for KS.

A Novel Cause of Bowel Obstruction in a Patient with Long-Standing Crohn's Disease

Solitary fibrous tumors are rare tumors of mesenchymal origin. Although most often observed in the lung pleura, they have been reported in varied extrapleural sites. A 70-year-old male with complicated Crohn's disease presented with 3 days of nausea, emesis, constipation, and abdominal pain. Computed Tomography (CT) demonstrated mucosal thickening of the middescending colon, consistent with fibrosing stricture. Surgical excision revealed an unusual, 5 cm mass originating in the subserosa. Histopathology of the lesion was notable for a proliferation of cells with spindle and stellate-shaped nuclei and no appreciable mitotic figures, which extended into the muscularis and submucosa. Immunohistochemistry was STAT6 nuclear positive and cytoplasmic CD34 positive, diagnostic for solitary fibrous tumor (SFT). In this case, the SFT infiltrating into the muscularis propria and subserosa caused the stricture and bowel obstruction. This illustrates that while fibrosing strictures are usually the etiology of bowel obstruction in the setting of Crohn's disease, other rare possible causes should be considered.

Fortuitous Eradication of an Aggressive Basal Cell Carcinoma Via Foreign Body Reaction to a Polyurethane Vacuum-Assisted Closure Sponge

ABSTRACT

The foreign body reaction (FBR) is a well-documented immune reaction. Much of the literature on FBRs has focused on minimizing this immune response to mitigate the impact on medical implants. Here, we present a case that illustrates a serendipitous oncologic outcome from an FBR. A 54-year-old man presented with an aggressive basal cell carcinoma (BCC). At the first resection, he had broadly positive surgical margins. The surgical wound was temporized with a polyurethane wound vacuum assisted closure (VAC) device. He was lost to follow-up having retained a VAC sponge for a total of 12 weeks. A wide re-resection was performed 7 months after the initial resection. Exhaustive examination of the resected specimen was performed. There was an absence of any BCC, replaced by a widespread chronic FBR to polyurethane VAC sponge particles. This suggests that the foreign body immune response was sufficiently intense to eradicate any remaining BCC. This case illustrates the concept of an FBR as a novel method of local immunotherapy.

Urticarial vasculitis: A potential signpost for multisystem inflammatory syndrome in children

Multisystem inflammatory syndrome in children (MIS-C) is a rare and serious complication of Sars-Cov-2 infection. Dermatologic manifestations are present in the majority of patients. Skin lesions found in children with MIS-C are classified into four categories: morbilliform, reticulated, scarlatiniform, and urticarial lesions. Clinicopathologic characterization within these categories is limited. Thus, we present a clear example of an urticarial lesion in the context of MIS-C with well-documented clinicopathologic phenomena. A previously healthy 16-year-old female presented with 3 weeks of an itchy, burning rash initially presenting on her right forearm (and lasting greater than 24 hours without migration) before spreading diffusely. She also reported fever, cough, myalgias, nausea, and vomiting of 4 weeks' duration. Physical examination revealed an edematous, maculopapular, nonblanching, erythematous rash covering the patient's upper extremities, abdomen, back, anterior thighs, and face. The patient tested positive for COVID-19. A low-grade leukocytoclastic vasculitis was noted along with intraluminal fibrin and rare microthrombi in vessels of the mid to deep dermis. The patient was diagnosed with MIS-C and urticarial vasculitis. She was treated with steroids and naproxen for subsequent MIS-C flares. Dapsone treatment was started for the urticarial vasculitis.

Noncanonical NF-κB Signaling Upregulation in Inflammatory Bowel Disease Patients is Associated With Loss of Response to Anti-TNF Agents

Objectives: Targeting tumor necrosis factor (TNF) with biologic agents, such as infliximab and adalimumab, is a widely used and effective therapeutic strategy in inflammatory bowel disease (IBD). Unfortunately, a significant number of patients fail to respond or lose response over time to these agents. Previous studies have defined multiple complex roles for canonical NF-κB signaling in the pathogenesis of IBD. However, preliminary evidence suggests that the lesser defined noncanonical NF-κB signaling pathway also contributes to disease pathogenesis and response to anti-TNF agents. The objective of this study was to evaluate this hypothesis in Crohn’s disease (CD) and ulcerative colitis (UC) patients.

Design: A total of 27 subjects with IBD (19 with CD and 8 with UC) and 15 control subjects were tested. Clinical criteria, patient history, and endoscopic disease activity were factors used to categorize patients and define therapeutic response. Biopsy specimens were collected during colonoscopy and expression was determined for 88 target genes known to be associated with noncanonical NF-κB signaling and IBD.

Results: Noncanonical NF-κB signaling was significantly upregulated in IBD patients and was associated with increased gastrointestinal inflammation, epithelial cell death, lymphocyte migration, and Nod-like receptor signaling. Furthermore, noncanonical NF-κB signaling was further upregulated in patients unresponsive to anti-TNF agents and was suppressed in responsive patients. MAP3K14, NFKB2, CCL19, CXCL12, and CXCL13 were significantly dysregulated, as were genes that encode pathway regulators, such as CYLD, NLRP12, and BIRC2/3.

Conclusion: Our study identifies a previously uncharacterized role for the understudied noncanonical NF-κB signaling pathway in the pathogenesis of IBD and anti-TNF therapy responsiveness. The genes and pathways identified may ultimately prove useful in IBD management and could potentially be used as biomarkers of drug response.

Rare mimic of angiosarcoma: Erythema ab igne with reactive angiomatosis

Erythema ab igne is an uncommon physical dermatosis that presents with localized patches of reticulated erythema and hyperpigmentation corresponding with the underlying dermal venous plexus. The rash occurs in response to chronic heat exposure that does not meet the threshold for thermal burn of the skin. The histopathologic findings are characterized by atrophy and thinning of the epidermis, focal hyperkeratosis, and keratinocyte atypia. The dermis displays dilated capillaries, evidence of pigment incontinence, and prominent elastotic material. We report a case of a 65-year-old male who presented to his primary care physician with a 1-year history of reticular erythema and hyperpigmentation with focal ulceration on his right lateral leg. Histopathology on biopsy revealed mild hyperkeratosis and focal epidermal atrophy; however, the most striking finding was a proliferation of dermal vascular spaces lined by pleomorphic endothelial cells and numerous mitotic figures, which was morphologically compatible with angiosarcoma. However, clinicopathologic correlation and immunostaining revealed an actual diagnosis of erythema ab igne with reactive angiomatosis. Reactive angiomatosis-morphologically mimicking angiosarcoma-is a rarely reported feature of severe erythema ab igne, and dermatopathologists should be aware of this possibility to avoid misdiagnosis of erythema ab igne as angiosarcoma.

Pleomorphic Leiomyosarcoma Presenting as a Upper Back Epidermal Inclusion Cyst

ABSTRACT

Leiomyosarcoma is a common sarcoma of both organs and soft tissues; however, large intradermal tumors are extremely rare. Presented is a pleomorphic leiomyosarcoma in a 64-year-old man, initially considered to be a ruptured epidermal inclusion cyst. The patient had a mildly tender, enlarging soft-tissue mass with a central pore on his right upper back. Incomplete extirpation showed a 5 × 5 cm heterogeneous, predominantly pleomorphic sarcoma with areas of fascicular and storiform spindled cells infiltrating the subcutaneous soft tissue to the underlying fascia and extending upward into the middle and upper dermis with prominent extension into pilosebaceous units. There were small foci with myxoid stroma and large areas of necrosis. CD31 demonstrated thin-walled curvilinear vessels throughout the tumor. The first desmin immunohistochemical stain near areas with myxoid stroma was negative but smooth muscle actin positive. However, desmin positivity was strong and diffuse in the spindled and more pleomorphic areas on 2 additional tissue sections. No rhabdomyoblasts or striated muscle fibers were seen. A diagnosis of pleomorphic leiomyosarcoma was rendered. This case highlights a unique clinical and histological presentation of a leiomyosarcoma initially mistaken to be a ruptured epidermal inclusion cyst, and the need to sometimes apply ancillary immunohistochemical studies to sections from more than one tissue block to accurately differentiate heterogeneous sarcomas with similar histologic features.

Intraneural Peroneal Ganglion Cyst Excision in a Pediatric Patient: A Case Report

CASE

A 14-year-old female presented with a profound foot drop after trauma to the right leg. Clinical examination and electrodiagnostic studies demonstrated a dense palsy of the common peroneal nerve. Magnetic resonance imaging revealed an intraneural peroneal ganglion cyst at the fibular neck. Surgical treatment included decompression and transection of the articular branch to the proximal tibiofibular joint. At the 1-year follow-up, the patient demonstrated complete recovery of peroneal nerve function.

CONCLUSIONS

This case demonstrates a rare finding of a pediatric intraneural peroneal ganglion cyst. The presentation and treatment is well-documented and adds depth to the literature on a sparsely reported condition.

McArdle Disease vs. Stiff-Person Syndrome: A Case Report Highlighting the Similarities Between Two Rare and Distinct Disorders

McArdle disease is a rare autosomal recessive disorder of muscle glycogen metabolism that presents with pain and fatigue during exercise. Stiff-Person Syndrome is an autoimmune-related neurologic process characterized by fluctuating muscle rigidity and spasm. Reported is a 41-year-old male who presented to the emergency department due to sudden-onset weakness and chest pain while moving his refrigerator at home. Cardiac workup was non-contributory, but a creatine kinase level > 6,000 warranted a muscle biopsy. The biopsy pathology report was misinterpreted to be diagnostic for McArdle disease given the clinical presentation. After 4 years of treatment without symptomatic improvement, a gradual transition of symptoms from pain alone to pain with stiffness was noted. A positive glutamic acid decarboxylase antibody test resulted in a change of diagnosis to Stiff-Person Syndrome. This is the first known case that highlights the similarities between these two rare and distinct disease processes, highlighting the necessity for thorough history taking, maintenance of a broad differential diagnosis, and knowledge of how best to interpret complex pathology reports.

Hidradenitis suppurativa at the knees

Hidradenitis suppurativa is a poorly understood, destructive disease centered on pilosebaceous units and characterized by inflammatory nodules that progress to abscesses, sinus tracts, and scars. The typical patient is a young woman with involvement of the axillae, breasts, and groin. Presented is a 60-year-old man with poorly controlled diabetes, who initially developed pink-to-yellowish plaques with punched out ulcers on his knees that evolved to scars and draining sinus tracts. Draining sinus tracts were also noted under the left axilla. Histopathology revealed suppurative granulomatous inflammation centered on hair follicles as well as sinus tracts. Special stains for fungus and mycobacterial bacilli were negative. Cultures and PCR for mycobacterial tuberculosis were negative. The patient was diagnosed with hidradenitis suppurativa. A treatment trial of topical corticosteroids and antibiotics was given, but this regimen failed to improve his lesions. The patient was then started on adalimumab, which yielded marked improvement within three months. This case is reported because of the unusual clinical presentation and to highlight the spectrum of atypical hidradenitis suppurativa.

Patient Derived Xenografts Expand Human Primary Pancreatic Tumor Tissue Availability for ex vivo Irreversible Electroporation Testing

New methods of tumor ablation have shown exciting efficacy in pre-clinical models but often demonstrate limited success in the clinic. Due to a lack of quality or quantity in primary malignant tissue specimens, therapeutic development and optimization studies are typically conducted on healthy tissue or cell-line derived rodent tumors that don't allow for high resolution modeling of mechanical, chemical, and biological properties. These surrogates do not accurately recapitulate many critical components of the tumor microenvironment that can impact in situ treatment success. Here, we propose utilizing patient-derived xenograft (PDX) models to propagate clinically relevant tumor specimens for the optimization and development of novel tumor ablation modalities. Specimens from three individual pancreatic ductal adenocarcinoma (PDAC) patients were utilized to generate PDX models. This process generated 15-18 tumors that were allowed to expand to 1.5 cm in diameter over the course of 50-70 days. The PDX tumors were morphologically and pathologically identical to primary tumor tissue. Likewise, the PDX tumors were also found to be physiologically superior to other in vitro and ex vivo models based on immortalized cell lines. We utilized the PDX tumors to refine and optimize irreversible electroporation (IRE) treatment parameters. IRE, a novel, non-thermal tumor ablation modality, is being evaluated in a diverse range of cancer clinical trials including pancreatic cancer. The PDX tumors were compared against either Pan02 mouse derived tumors or resected tissue from human PDAC patients. The PDX tumors demonstrated similar changes in electrical conductivity and Joule heating following IRE treatment. Computational modeling revealed a high similarity in the predicted ablation size of the PDX tumors that closely correlate with the data generated with the primary human pancreatic tumor tissue. Gene expression analysis revealed that IRE treatment resulted in an increase in biological pathway signaling associated with interferon gamma signaling, necrosis and mitochondria dysfunction, suggesting potential co-therapy targets. Together, these findings highlight the utility of the PDX system in tumor ablation modeling for IRE and increasing clinical application efficacy. It is also feasible that the use of PDX models will significantly benefit other ablation modality testing beyond IRE.

A Cribriform Cancer Metastatic to Liver: Case Report and Literature Review

Metastasis from salivary gland tumors to liver is exceedingly uncommon. Reported is the first case of a mammary analog secretory carcinoma (MASC) of salivary gland origin metastasized to the liver, even after complete surgical resection. A 76 year old female, with past history of a completely extirpated right parotid gland MASC, presented 2 years after right superficial parotidectomy and right neck dissection, with back and flank pain. Subsequent abdominal and pelvic CT revealed multiple small hepatic lesions. Biopsy of the largest hepatic lesion confirmed metastatic MASC of primary parotid gland origin. Both the parotid primary and the hepatic metastases had the confirmatory ETV6 rearrangement by fluorescence in situ hybridization. Although high-grade malignancy and distant metastases of MASC of salivary gland origin to liver is rare, recognizing metastatic MASC potentially alters prognosis and determines therapeutic options.

Endometriosis of the Eyelid, an Extraordinary Extra-abdominal Location Highlighting the Spectrum of Disease

Cutaneous endometriosis is an uncommon dermatologic disorder predominantly seen in young women. Most commonly, it presents within a region of a previous surgical scar, often in relation to a gynecologic procedure on the abdomen or in close proximity to the umbilicus. The typical clinical presentation is that of papules or nodules with monthly cyclical pain and size variation. Histologically, the lesions are composed of endometrial stroma and glands. The pathophysiology is not well understood but is believed to be due to metastasis or seeding of endometrial cells. When this uncommon disorder occurs outside of the most typical clinical setting, it may cause some diagnostic difficulty. In this report, we present the first known case of cutaneous endometriosis on the eyelid.

Gallbladder Metastases: A Report of Two Cases

Introduction

Metastasis to the gallbladder is not common and usually manifests an advanced stage of malignancy. Herein, we report a case of triple negative high grade invasive ductal carcinoma of breast with a metastatic lesion to the gallbladder.

Case Presentation

The patient is a 52-year-old female diagnosed with invasive ductal carcinoma treated with mastectomy and chemotherapy. After 12 months, she presented to the emergency department with right upper quadrant pain and elevated liver chemistries. Abdominal enhanced computed tomography showed periportal and gallbladder wall edema. After cholecystectomy, the resected gallbladder was histologically considered to be a metastatic lesion arising from the primary lung cancer. The second case describes a case of a 77-year-old woman with multiple co-morbidities who presented to the hospital with sepsis secondary to biliary source. Abdominal enhanced computed tomography findings were concerning for acute cholecystitis. After cholecystectomy, the pathology of the resected gallbladder demonstrated cholecystitis and plasmacytoma.

Conclusion

The atypical presentation of gallbladder metastases could mislead treating providers. The diagnosis might alter management decisions and prognosis.

Primary tracheal hyalinizing clear cell carcinoma

Hyalinizing clear cell carcinomas (HCCC), now referred to as clear cell carcinomas (CCC) by the World Health Organization (WHO), are rare tumors usually arising from the salivary glands of the head and neck. We present the first case of a CCC originating from the trachea. A 66 year-old woman with history of hypertension, former smoker, presented to the emergency department reporting worsening shortness of breath. Computed chest tomography revealed a polypoid mass arising from the left posterior-lateral wall of the trachea. The patient developed worsening respiratory failure requiring mechanical ventilation. Bronchoscopy was completed which relieved a malignant airway obstruction and pathology revealed nests of cells with monomorphic nuclei and clear cytoplasm set in a hyalinized stroma. Using break apart probe fluorescence in situ hybridization testing the tissue revealed the presence of a recurring translocation of the Ewing sarcoma (EWSR1) gene, confirming the diagnosis. CCC is a rare primary airway tumor. CCC was first reported to originate in the lung in 2015. We present the first case of CCC arising from the trachea.