Fumarate Hydratase-Deficient Abdominal Wall Leiomyoma Presenting a Decade Post-Fumarate Hydratase-Deficient Uterine Leiomyoma Excision: An Incidental or Syndromic Association?

Background. The occurrence of fumarate hydratase-deficient leiomyoma of the abdominal wall is exceptionally rare. Case Presentation. A 50-year-old female patient with a past medical history of fumarate hydratase-deficient uterine leiomyoma presented with a left lower quadrant abdominal mass that has been present for the past 2 years. An ultrasound revealed a 3.5 cm oval hypoechoic mass. A subsequent CT scan showed a 3.5 cm hyperdense mass within the left internal oblique musculature. No family history is noted. A biopsy of the mass exhibited bundles of spindle cell neoplasm exhibiting bizarre ovoid nuclei and eosinophilic cytoplasm. No evidence of mitotic figures or tumor necrosis was noted. Immunohistochemical staining showed positive staining for desmin and smooth muscle actin (SMA), but negative staining for MART-1, S100, and CD34. Lesional cells showed expression of 2-succinocysteine and loss of fumarate hydratase expression. A diagnosis of fumarate hydratase-deficient leiomyoma was rendered. Conclusion. This report reinforces the importance of considering genetic testing for fumarate hydratase mutations in the evaluation of extra-uterine leiomyomatous lesions. Comprehensive follow-up and clinical screening in individuals with new lesions and a known history of fumarate hydratase-deficient neoplasms is mandatory. Recent recommendations support the integration of morphology-based evaluation along with immunohistochemical staining and genetic testing as a part of the standard evaluation for all uterine leiomyomas.

Unveiling the Uncommon: Gastrointestinal Basidiobolomycosis of the Colon and its Distinctive Splendore-Hoeppli Phenomenon.

BACKGROUND: Basidiobolomycosis is a rare fungal infection caused by Basidiobolus ranarum. CASE PRESENTATION: A 53-year-old man from Saudi Arabia with a known history of diverticulosis presented with severe abdominal pain and diarrhea. A CT scan revealed circumferential wall thickening of the descending and sigmoid colon with surrounding fat stranding, suggesting a diagnosis of complicated diverticulitis. Additional thick fluid was observed around the affected area. Surgical excision was pursued. A gross examination of two received large bowel segments disclosed marked ulcerated mucosa and wall thickening with exudate-covered serosal surfaces and adhesions. Microscopic examination unveiled significant infiltration by eosinophils, polymorphonuclear leukocytes, and granulomatous inflammation. Thin-walled, broad fungal hyphae of Basidiobolus, surrounded by eosinophilic material, were identified. Granulomas displayed abundant multinucleated giant cells and palisading histiocytes around central necrosis or abscess formation. Thin-walled, broad fungal hyphae of Basidiobolus, with sparse septations, are surrounded by a radiating, intensely eosinophilic cuff (Splendore-Hoeppli phenomenon). These hyphae, visible with hematoxylin and eosin staining, were further highlighted with periodic acid-Schiff and Gomori methenamine silver staining. DISCUSSION: Basidiobolomycosis may mimic neoplastic lesions. Histologically, the characteristic features include broad, thin-walled septate hyphae surrounded by eosinophilic material, a finding that is accentuated by the Splendore-Hoeppli phenomenon. Microscopic examination, along with special stains such as periodic acid-Schiff (PAS) and Gomori methenamine silver, is essential for accurate diagnosis. CONCLUSION: Prompt recognition and appropriate antifungal therapy are vital for favorable patient outcomes. This report highlights the distinctive features of Basidiobolomycosis to raise awareness and understanding of this infrequent yet clinically significant fungal infection.

Pulmonary Langerhans Cell Histiocytosis Post-Hodgkin Lymphoma Completely Resolved With Vinblastine in a Heavy Smoker: Coincidence or Causation?

The association among Langerhans cell histiocytosis, hematolymphoid malignancies, and heavy smoking has been addressed in medical literature to identify a possible potential link. Such occurrence can pose diagnostic challenges, as well as important clinical implications for disease progression and treatment approaches. We present pulmonary Langerhans cell histiocytosis instance in a 35-year-old male patient, with a 34-pack-year smoking history and nodular sclerosing Hodgkin lymphoma stage IIB who developed multiple bilateral lung nodules. The patient completed 6 cycles of doxorubicin (Adriamycin), bleomycin, vinblastine, and dacarbazine chemotherapy and radiotherapy 2 years earlier. CT chest scans revealed numerous micronodules scattered randomly throughout the upper and lower left lung lobes. Subsequent wedge resection exhibited cellular proliferation with grooved nuclei, eosinophilic cytoplasm, and surrounding inflammatory components. Immunohistochemical staining showed positive staining for S100 and CD1a confirming a diagnosis of pulmonary Langerhans cell histiocytosis. The patient responded to a 6-week treatment with vinblastine and prednisolone. A subsequent CT scan of the lungs revealed complete resolution after 3 years. This report underscores the importance of identifying pulmonary Langerhans cell histiocytosis in heavy smokers with Hodgkin lymphoma presenting with multiple nodular pulmonary lesions. For patients with Hodgkin lymphoma and a possible genetic predisposition, smoking may contribute to the overt development of pulmonary Langerhans cell histiocytosis. Therefore, smoking cessation and careful follow-up examinations are required. Further research is recommended to elucidate the underlying mechanisms of this intriguing association.

Cutaneous Syncytial Myoepithelioma: An Uncommon and Distinct Variant of Cutaneous Epithelioid Neoplasm.

BACKGROUND: Cutaneous syncytial myoepithelioma (CSM) is an uncommon and distinct variant of cutaneous myoepithelioma. We aim to present a case of CSM to enhance the recognition of this unique variant, encompassing its clinical characteristics, histopathological features, immunohistochemical staining, and therapeutic approaches. CASE PRESENTATION: A 10-year-old girl presented with a dome-shaped nodule located on the skin of her left medial distal arm. Microscopic examination of the skin biopsy revealed a well-defined dermal nodular lesion, surrounded by an epidermal collarette. Tumor cells were composed of epithelioid to spindle-shaped cells with round-to-oval nuclei, small nucleoli, and abundant eosinophilic cytoplasm with a syncytial-like growth pattern. A moderate degree of nuclear pleomorphism was noted. Mitotic activity was not prominent. Immunohistochemical staining revealed positive staining for epithelial membrane antigen, GLUT1, collagen IV, and S100. Smooth muscle actin, CD10, and CD68 showed patchy positivity. CD31, CD34, p63, SOX10, anaplastic lymphoma kinase (ALK), glial fibrillary acidic protein, pankeratin (AE1/AE3/PCK26), Melan-A, and CD1a were negative. Fluorescence in situ hybridization targeting TFE3 and ALK genes was negative. The differential diagnosis included ALK-negative epithelioid cell histiocytoma, epithelioid perineurioma, and CSM. Based on the above findings, a diagnosis of CSM was rendered. DISCUSSION: CSM is a benign cutaneous neoplasm composed of sheets of histiocytoid or short spindle cells with pale eosinophilic cytoplasm with a syncytial-like growth pattern. Clinically, CSM often presents as a painless, slow-growing nodule or plaque in a broad anatomical distribution with a preference for the distal extremities.. CSM is characteristically positive for epithelial membrane antigen (EMA) and S100 protein and negative for keratins. In challenging cases, molecular testing for EWSR1 gene rearrangement and EWSR1-PBX3 gene fusion aid in confirming the diagnosis. CONCLUSIONS: The histologic features of CSM present a unique set of challenges posing a diagnostic dilemma, as they can bear resemblance to a range of benign and malignant cutaneous neoplasms including ALK-negative epithelioid cell histiocytoma, epithelioid perineurioma, malignant or nevoid melanoma, and epithelioid sarcoma. An accurate diagnosis is crucial for guiding proper clinical management considering that this entity typically demonstrates an excellent prognosis following a complete surgical excision.

Lymphangitic Melanomatosis: Case Report of Intralymphatic Spread of Melanoma in a 66-year-old Man.

ABSTRACT: Melanoma with lymphatic invasion has been associated with increased risk of metastasis, but the mechanisms and clinical implications are poorly understood. Although current reports have documented angiotropic spread of melanoma and suggest lymphatic spread of melanoma to increase the likelihood of metastasis, to our knowledge, lymphangitic metastatic melanoma resembling cutaneous carcinomatosis or presenting with facial hyperpigmentation has not been described. In this case report, we describe extensive cutaneous intralymphatic spread of melanoma, or lymphangitic melanomatosis, producing macular skin pigmentation in a 66-year-old man.

Erythema Multiforme-Like Fixed Drug Eruption During Azathioprine and Hydroxychloroquine Treatment for Systemic Lupus Erythematosus Mimicking Rowell Syndrome: A Rare and Challenging Clinical Scenario.

Background. Fixed drug eruption and Rowell syndrome stand as intriguing entities with overlapping clinical and pathological features. Case Presentation. A 32-year-old female patient presented with a tender and pruritic rash on the left upper chest for 3 days. Clinical examination revealed a flaring rash on the chest, under her left eye, tongue, and lips. The patient had a significant past medical history of systemic lupus erythematous with positive (ANA, Sm, dsDNA, ribosomalP, RNP) antibodies, hypocomplementemia, inflammatory arthritis, discoid lupus, leukopenia, thrombocytopenia, and immune thrombocytopenic purpura, and avascular necrosis affecting both hips and her right knee. At the time of presentation, the patient was on azathioprine 150 mg daily and hydroxychloroquine 200 mg twice daily. Skin biopsy of the left upper chest revealed interface dermatitis with necrotic keratinocytes at the dermal-epidermal junction. Superficial and, in some areas, deep perivascular and peri adnexal lymphocytic infiltrates were observed, accompanied by eosinophils. CD123 staining highlighted 16% of the inflammatory cells. Direct Immunofluorescence for IgG, IgA, IgM, C3, and fibrinogen revealed positive linear basement membrane staining for IgG and fibrinogen, with no significant staining for the remaining immunoreactants. Considering the patient's history of medicine usage, and negative SS-A and SS-B antibody, a fixed drug eruption was favored. Discussion. This article discusses the clinical presentations, pathophysiological mechanisms, and diagnostic criteria for fixed drug eruption and Rowell syndrome. Conclusion. Awareness of the distinct clinical and histopathologic features of fixed drug eruption and Rowell syndrome, particularly when sharing cutaneous manifestations, underscores the importance of a comprehensive diagnostic approach and laboratory testing.

Myxoid neurofibroma masquerading as lymphatic-venous malformation and poses a diagnostic challenge on fine needle aspiration biopsy.

BACKGROUND: Myxoid neurofibromas (NF) are uncommon, benign spindle cell tumors that originate from peripheral nerve sheaths, often posing a diagnostic challenge due to their hypocellularity on cytology specimens. Distinguishing myxoid spindle cell lesions can be challenging, given the broad range of potential differential diagnoses. CASE PRESENTATION: A 26-year-old female with a past medical history of embolized inguinal, flank, and retroperitoneal venolymphatic malformation presented with a left pelvic pain causing significant disability. CT scan showed an extensive 8.7 cm × 6.6 cm retroperitoneal mass. FNA was performed and alcohol-fixed papanicolaou-stained smears showed a hypocellular specimen with loosely arranged clusters of bland spindle cell proliferation in the background of a mucoid matrix. Spindle cells showed scant cytoplasm and elongated oval-shaped regular nuclei. Prominent nucleoli were not seen. An excisional biopsy revealed a bland spindle cell proliferation in a myxoid background associated with shredded collagen bundles. Immunohistochemical staining showed diffuse positivity for S100 and CD34. Based on the overall findings, a definitive diagnosis of myxoid neurofibroma was rendered. DISCUSSION: Cytological features of myxoid neurofibroma include the presence of hypocellular spindle-shaped cells arranged in small, loosely organized groups within a myxoid matrix background. Cells exhibit scant cytoplasm with regular oval and elongated nuclei. Nucleoli are typically not identified. The differential diagnosis includes myxoid neurofibroma, myxoma, myxoid liposarcoma, myxoid chondrosarcoma, myxoid dermatofibrosarcoma protuberans, low-grade fibromyxoid sarcoma, and low-grade myxo-fibrosarcoma. CONCLUSION: We aim to highlight the importance of considering myxoid neurofibroma in the differential diagnosis of hypocellular myxoid spindle cell lesions encountered on fine-needle aspiration cytology.

Malignant Para-Testicular Mesothelioma: A Rare Presentation in the Tunica Vaginalis of an Elderly Male With No Prior Asbestos Exposure.

Malignant mesothelioma of the tunica vaginalis is an extremely rare and aggressive tumor that is frequently encountered in elderly patients. The diagnosis of malignant mesothelioma of the tunica vaginalis poses a diagnostic challenge due to its infrequency and nonspecific clinical presentation. Histopathological examination and immunohistochemical staining are essential in differentiating this tumor from other para-testicular masses and establishing a definitive diagnosis. Early detection and comprehensive treatment planning are crucial for improving the prognosis and overall outcomes for patients with this rare malignancy. We present a report of malignant mesothelioma of the tunica vaginalis in a 78-year-old male patient with no history of asbestos exposure who presented with a large infiltrative left para-testicular mass. Histopathological examination revealed a biphasic proliferation composed of epithelioid and spindle cells with infiltrative features, foci of necrosis, and increased mitotic figures. Immunohistochemical staining exhibited positive staining for WT1, D2-40, and calretinin, supporting the mesothelial origin of the tumor. Notably, BerEP4 staining was negative, arguing against carcinoma. Immunostaining for keratin 5 was positive, supporting the mesothelial differentiation. The Ki67 proliferation index was high. The differential diagnosis included adenomatoid tumors, germ cell tumors, and pleomorphic sarcoma. We aim to discuss the clinical presentation, diagnostic approach, and therapeutic approaches of this rare entity.

Extra-Ocular Sebaceous Carcinoma in Situ of the Arm of an Elder Male: An Unusual Presentation in an Atypical Location.

Background. Sebaceous carcinoma in situ outside the ocular region is an exceedingly uncommon. It is an intraepidermal neoplasm originating from sebaceous glands limited to the epidermis with no invasion into the underlying dermis or beyond. Although sebaceous carcinoma in situ is predominantly observed in ocular regions, particularly the eyelids, instances of its occurrence in extraocular locations are infrequent, with only a limited number of examples reported in the literature. Case Presentation. A 63-year-old man presented with a left posterior arm lesion. Microscopic examination revealed a proliferation of poorly differentiated atypical neoplastic sebocytes confined to the epidermis with pleomorphic nuclei, prominent nucleoli, and clear cell changes. The neoplastic cells demonstrated positive staining for adipophilin, androgen receptor, epithelial membrane antigen, P63, BerEP4, and keratin 7. Microsatellite instability markers showed preserved nuclear staining for MLH1, PMS2, MSH2, and MSH6. A definitive diagnosis of sebaceous carcinoma in situ was rendered. Discussion. The distinctive histopathologic characteristics typically involve the presence of atypical sebaceous cells confined within the epidermis. Atypical cells often exhibit enlarged nuclei, increased mitotic activity, and prominent nucleoli. A panel of epithelial membrane antigen, adipophilin, and androgen receptors is essential for ensuring an accurate diagnosis. Conclusion. This report underscores the importance of considering sebaceous carcinoma in situ in diagnosis in atypical locations, emphasizing the need for a comprehensive histopathologic examination and immunohistochemical staining panel. This article aims to demonstrate the rarity of sebaceous carcinoma in situ in extraocular sites to broaden our understanding of its diverse clinical presentations.

High-Grade Spindle Cell Sarcoma of the Scalp With an MGA::NUTM1 Gene Fusion in a Pediatric Patient.

ABSTRACT: NUT carcinoma (NC) is a rare and aggressive neoplasm associated with a poor prognosis. NC is characterized by a NUTM1- rearrangement on chromosome 15q14, commonly fused with the BRD4 or BRD3 gene . A rare subset of NC defined by fusion of NUTM1 with the MGA gene has been identified, showing mesenchymal differentiation on histology. Few cases of spindle cell sarcomas harboring MGA::NUTM1 gene fusions have been reported in the literature. We describe a case of spindle cell sarcoma harboring an MGA::NUTM1 fusion in a 6-year-old male patient. In contrast to typical cases of spindle cell carcinomas or NC, NUTM1 fusion-positive sarcomas are associated with a better prognosis. This report highlights the importance of diagnostic workup of undifferentiated neoplasms, as identification of the MGA::NUTM1 fusion in spindle cell sarcoma could be used in treatment algorithms and lead to better outcomes, to the benefit of patients.