Primary adenosquamous carcinoma of the colon is exceedingly rare and accounts for a clinically aggressive minority of colonic epithelial malignancies, with metastatic disease identified in 36% to 49% of cases at the time of diagnosis or resection, compared to 14% of conventional adenocarcinoma cases. Reported median overall survival time is less than half of that for conventional colonic adenocarcinoma, supporting inclusion of squamous differentiation as an adverse prognostic factor. Due to its rarity, optimal treatment protocols have yet to be standardized. We present the case of a 61-year-old female who underwent emergent right hemicolectomy due to bowel obstruction secondary to an ileocecal mass discovered on imaging. Gross examination revealed a 7.3-cm, primarily submucosal cecal mass involving the appendix with associated ileocolic adhesion. Histologic examination showed carcinoma with distinct areas of glandular and squamous differentiation, exhibiting the anticipated differential expression patterns of CK5/6, p63, CK20, CDX2, and mucicarmine. Immunohistochemistry for p16 was negative in both components. The adenocarcinoma component was continuous with a small focus of dysplastic colonic surface epithelium, supportive of cecal origin. Eight of 19 lymph nodes were positive for squamous and adenocarcinomatous metastasis, and a concurrent liver biopsy was also positive for metastasis. There was no evidence of mismatch repair protein deficiency by immunohistochemistry, which was performed on tissue containing both glandular and squamous components. We share this case to highlight a rare and uniquely aggressive subtype of a routinely encountered malignancy, reinforcing the importance of identifying and reporting squamous differentiation within cases of colonic adenocarcinoma.

HighlightsMesenteric cystic masses account for a very small fraction of abdominal pain cases.Symptoms arise likely as a result of mass effect, even when these lesions are small.On detection of these lesions by imaging, it is important to exclude neuroendocrine tumors.Complete surgical excision is curative of symptoms caused by local mass effect.Histopathological examination of specimens is the definitive means to differentiate between such lesions, that appear similarly on imaging.

Introduction/Objective Proliferating pilar tumor is a rare cutaneous adnexal neoplasm, closely resembling and potentially misdiagnosed as conventional squamous cell carcinoma. Malignant forms are recognized; however, differentiating criteria have not been firmly established due to their exceptional rarity. Prognosis is variable, with recurrence or metastasis reported in up to 25% of patients within a very small data set. Methods We present a case of a 31 year old male who underwent excision of a posterior neck mass clinically presumed to be a recurrent benign cyst in 2018. Initial excision was performed at an outside institution approximately 10 years prior, and a pathology report was not included in his record. Results Our resection specimen contained a 5.5 cm lobulated, cystic and solid mass involving the dermis and subcutis with superficial ulceration. Tumor histology was consistent with malignant proliferating pilar tumor as described in other reported cases, showing a proliferation of pleomorphic squamous cells infiltrating the dermis and associated desmoplasia. The tumor featured abundant pilar keratinization with focal necrosis and increased mitotic activity. Numerous smaller pilar cysts exhibiting varying degrees of squamous atypia studded the periphery of the dominant mass. The immunohistochemical profile of this case also exhibited similarities to other reports, with focal positivity for calretinin and CD34 as well as an increased Ki-67 proliferative index (up to 70–80%). While other reports document diffuse expression of p53, our case demonstrated complete absence of p53 staining. Conclusion We present this case to highlight the importance of recognizing pilar differentiation within squamous lesions, examine pathologic features associated with malignant behavior, and discuss the relationship between histologic characteristics and clinical outcomes in this exceedingly rare tumor group.

Introduction/Objective Eosinophilic (Loffler) myocarditis is a rare disease defined by the influx of eosinophils into the endocardium and myocardium. Etiologies are numerous and include drug or hypersensitivity reactions, hypereosinophilic syndrome, hematologic malignancies, and parasitic infections. It is a diagnostically challenging entity. Presenting symptoms recorded in the literature are indefinite and nonspecific; heart failure, demonstrable arrhythmia, and elevated cardiac biomarkers. This is especially the case among younger, otherwise healthy patients without classical risk factors for atherosclerotic coronary artery disease. Methods Herein we present several cases of sudden cardiac death in young adults, including a case of unknown eosinophilic myocarditis, which highlights the potential trials in the diagnosis of this disease. Results Autopsies were performed on several adults (age range, 30-40 years) thought to have died of cardiac causes. This included a 30-year-old African American female with no significant known medical history who presented with a chief complaint of palpitations. The initial clinical impression at an outside institution was of cardiac amyloidosis. But the Technetium99 scan was inconclusive. Despite clinical management, she developed ventricular arrhythmias and could not be resuscitated. There was a vague history of taking nutritional supplements from a local grocery store. Gross findings at autopsy included circumferential subepicardial erythema, thymic enlargement (60g), and congested lungs. The heart was thoroughly sampled. Microscopic examination revealed diffuse infiltration of eosinophils, mast cells, lymphocytes and macrophages with mild myocyte necrosis and interstitial edema in all sections. There were no giant cells, no interstitial deposition of amorphous acellular material and no focus of infarcted myocardium. Thymic sections were histologically normal. Acetylcholine receptor antibody panel was negative. Conclusion We conclude that eosinophilic myocarditis though rare (0.5% unsuspected and 0.1% suspected cases), is a distinctive cause of death with a specific microscopic presentation. Our case also included thymic enlargement at autopsy – a finding not previously noted.

Introduction/Objective Enteropathy-associated T-cell lymphoma (EATL) is an aggressive peripheral T-cell lymphoma with a very poor prognosis. It is not uncommon for patients with EATL to present with intestinal obstruction or perforation, with the diagnosis made following surgical resection or autopsy. Although EATL is associated with celiac disease, this diagnosis may be made concomitant with EATL. The symptomology is often non-specific, particularly without a known history of celiac disease, and progression may be rapid. Methods/Case Report We describe the case of a 57 year old male who presented with several months of diarrhea, fatigue, night sweats, severe weight loss, and failure to thrive. Initial workup indicated positivity for Clostridium difficile and cryptosporidium, leading to antibiotic treatment. His symptoms persisted without significant improvement and a presumptive diagnosis of Crohn’s disease was made based on colonoscopy with biopsy and imaging that showed inflammatory changes with entero-enteric fistula formation. Further clinical decline necessitated exploratory laparotomy which revealed multiple enteric strictures, intra-loop abscesses, and necrotic ulceration necessitating segmental ileal resections. There was no associated lymphadenopathy. Microscopically, there was a dense, polymorphic lymphoid population within the bowel wall with associated mucosal ulceration and abundant necrosis. Striking anaplastic cytomorphology was present, with a heavy intratumoral eosinophilic infiltrate. Neoplastic lymphocytes were CD3+, CD30+ T cells with a CD7+, CD5-, CD4-, CD8-, CD56-, ALK- immunophenotype. The adjacent intestinal mucosa showed features of celiac disease (villous atrophy, intraepithelial lymphocytosis). Results (if a Case Study enter NA) NA Conclusion The prominent anaplastic morphology in combination with strong, diffuse CD30 expression prompted consideration of other T cell lymphomas, including anaplastic large cell lymphoma and peripheral T cell lymphoma, NOS, within the differential. The presence of coexisting histologic changes of celiac disease, dense eosinophilic infiltrate, and absence of lymphadenopathy were clues to the correct diagnosis. Notably, the frequency of CD30 expression in EATL is variable but common among cases manifesting large cell morphology.