Two Squamomelanocytic Tumors With Dendritic Melanocytes: Thoughts About Origin.

ABSTRACT: Cutaneous malignant squamomelanocytic tumor (SMT) is a rare neoplasm comprising 2 distinct cell populations of squamous cell carcinoma and a second component of either benign or malignant melanocytes. SMT most often presents as a keratotic papule in areas of chronic sun exposure, typically on the head or neck of middle-aged and elderly-aged, White male patient populations. In recent years, there has been an increase in case reports, including a review article published in 2023, identifying a total of 37 cases published in the literature. There are only 3 reported cases in the literature with spindled or dendritic cells in the melanocytic component, as most have been of the epithelioid subtype. Despite the increasing prevalence, the origin and pathophysiology is poorly understood. We report 2 cases of SMT with dendritic melanocytes that are centered around a hair follicle, proposing the theory that these 2 distinct cell types may arise from the hair follicles.

An Unexpected Post-Egg-Free Influenza Vaccine Granulomatous Reaction.

ABSTRACT: A 53-year-old woman presented with a pruritic plaque on the left upper arm that appeared following an egg-free flu vaccine due to a history of reaction to the standard vaccine. The affected area enlarged over a several month period immediately following vaccine administration. Physical examination revealed an 8 × 4 cm coalescent pink plaque on the left upper arm. A shave biopsy of the lesion showed dermal "naked" granulomas, or granulomas with sparse lymphocytic infiltrate at the margins, as typically seen in sarcoidosis. No foreign material was seen in the granulomatous reaction, including with polarization. Special stains, including acid fast bacilli, Grocott methenamine silver, periodic acid-Schiff, and Gram, were negative for organisms. The diagnosis of granulomatous dermatitis was made. Subsequent imaging demonstrated no findings suggestive of sarcoidosis. While vaccine-associated hypersensitivity reactions occur frequently, these reactions are typically due to individual vaccine components, such as egg protein, and do not normally result in the formulation of granulomas. Vaccination-induced granulomas are more often associated with the use of aluminum as an adjuvant; however, this is not present in the egg-free influenza vaccine. Thus, a granulomatous reaction to the egg-free influenza vaccine is very unusual and, to our knowledge, not previously reported.

A Rare Case of Emphysematous Gastritis Secondary to Organo-Axial Gastric Volvulus Associated With Sarcina ventriculi.

Gastric volvulus is a potentially life-threatening condition that can compromise the blood supply to the stomach predisposing to ischemia, eventually necrosis and cell death associated with gas-forming bacteria. Sarcina ventriculi has been associated with emphysematous gastritis also. We report a case of emphysematous gastritis associated with S. ventriculi in the setting of organo-axial gastric volvulus.

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.

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.

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.

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.

Metastatic Plasmacytoid Urothelial Carcinoma Masquerading as a Primary Signet Ring Cell Carcinoma of the Duodenum.

Plasmacytoid urothelial carcinoma can histologically mimic gastrointestinal signet ring cell carcinoma, a potential diagnostic pitfall resulting in improper clinical management. We present a rare case of a malignant duodenal ulcer due to metastasis from plasmacytoid urothelial carcinoma. Only by histological and retrospective immunohistochemical comparison with the primary bladder tumor was this revealed as a metastasis from a plasmacytoid urothelial carcinoma. This case report highlights the importance of clinical correlation and comparison with any previous pathology specimens, the limitations of immunohistochemical staining, and the utilization of both old and new immunohistochemical tools when differentiating signet ring cell carcinomas of primary sites versus potential metastases.

Multidisciplinary Inflammatory Bowel Disease Conference: The Impact of the Expert Pathologist on Patient Care.

BACKGROUND: Multidisciplinary teams (MDT) aid the diagnosis and management of patients with inflammatory bowel disease (IBD) and improve patient outcomes. The direct impact of a gastrointestinal expert pathologist on MDT care of IBD patients is unknown. METHODS: A retrospective chart review was conducted evaluating all cases (N = 289) discussed at the IBD MDT conference at Carilion Roanoke Memorial Hospital from June 1, 2013, through December 31, 2019. Cases were discussed between 1 and 6 times at the conference. Data collected included demographics, diagnosis before and after conference, reason for diagnostic change, endoscopy findings, medications, surgeries, and clinical follow-up. RESULTS: Approximately 15% to 42% of patients had a change in diagnosis after the first 3 conferences. The majority of diagnostic changes after the first (84%), second (73%), and third (67%) conferences were due to expert pathologist interpretation. Indeterminate colitis was the most frequently changed diagnosis, and Crohn's disease was the most common new diagnosis after conference. Among patients with a diagnostic change, 28.6% to 38.5% of patients had a change in their IBD medication regimen, and 7.7% to 10.9% had a surgical intervention after the first 2 conferences. Approximately 54.2% to 60% of patients reported clinical improvement or remission within 6 months of the first 3 conferences. CONCLUSION: The majority of diagnostic changes made at the multidisciplinary IBD conference were due to histopathologic re-interpretation. A change in diagnosis at times led to significant modifications in medical or surgical management. An expert gastrointestinal pathologist is an essential MDT member for IBD management.

An expert gastrointestinal pathologist plays a critical role in the diagnosis of patients presented at multidisciplinary team inflammatory bowel disease conferences. Their input at these conferences significantly impacts patients' medical and surgical management and clinical outcomes.

An Extraordinary Cause of Colonic Obstruction: Merkel Cell Carcinoma of Unknown Primary.

Merkel cell carcinoma is an aggressive and rare neuroendocrine skin cancer with documented metastases to the liver, lungs, and, seldom, the gastrointestinal tract. Metastases to the colon are rare but are seen with primary skin lesions or recurrent disease. Presented is a patient with large bowel obstruction secondary to a large hepatic flexure mass. Pathologic workup revealed Merkel cell carcinoma, and a dermatologic evaluation did not identify a primary cutaneous lesion. This is the first reported case of Merkel cell carcinoma of unknown primary presenting as large bowel obstruction.

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.

Papuloerythroderma of Ofuji in a Young Man.

Papuloerythroderma of Ofuji (PEO) is a rare skin disorder characterized by a distinctive pattern of pruritic, flat-topped, erythematous papules which coalesce into an erythroderma-like eruption with classic sparing of the skin folds. Although the pathogenesis of this condition is incompletely understood, previous reports have suggested a notable link between PEO and various forms of malignancy and immunocompromised states. Here, we report a case of a healthy young male with no comorbidities who presented with the classical features of PEO that responded well to combination therapy comprised of topical corticosteroids and phototherapy.