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ABSTRACT Langerhans cell histiocytosis (LCH), a disorder of antigen-presenting cells, is the commonest disorder of the mononuclear phagocytic system. Diagnosis is always challenging due to heterogeneous clinical presentation. However, with the evolution and better understanding of its biology, many of these children are being diagnosed early and offered appropriate therapy. Despite these advances, in developing countries, an early diagnosis is still challenging due to resource constraints for specialized tests. As a result, many patients succumb to their disease. Autopsy data on LCH is notably lacking in the literature. We sought to analyze the clinical (including mutational) and morphologic features at autopsy in six proven cases of LCH. This study includes a detailed clinico-pathological and mutational analysis of 6 proven cases of LCH. Presence of BRAF V600E mutation was assessed by both Real Time PCR and Sanger sequencing. A varied spectrum of organ involvement was noted with some rare and novel morphological findings, like nodular bronchiolocentric infiltration of LCH cells, lymphovascular emboli of LCH cells, and paucity of eosinophils within the infiltrate; these features have not been described earlier. Surprisingly, all cases were negative for BRAF V600E mutation on both RQ-PCR and Sanger sequencing. The present study is perhaps the first autopsy series on LCH. This extensive autopsy analysis represents a correlation of pathological features with clinical symptoms which provides clues for a timely diagnosis and appropriate therapeutic intervention. Also, our findings hint at the low frequency of BRAF V600E mutation in our LCH patients.

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ABSTRACT Hepatoid adenocarcinoma of the lung is a rare subtype of lung cancer. We report a case of a metastatic hepatoid adenocarcinoma of the lung with aggressive behavior, including biopsy and autopsy findings. The pulmonary tumors showed features indistinguishable from hepatocellular carcinoma and were diffusely positive for Hepatocyte Paraffin 1.

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ABSTRACT Diaphragmatic eventration (DE) associated with intestinal malrotation and renal agenesis is a rare entity. The authors report a case of a 69-year-old man who had symptoms of heart failure. He had a previous imaging diagnosis of right diaphragmatic eventration and dilated cardiomyopathy. He died on the second day after the hospital admission and had a post mortem examination that confirmed complete right diaphragmatic eventration, intestinal malrotation, left renal agenesis, dilated cardiomyopathy, and anteriorly rotated right kidney and had findings suggestive of a thoracoabdominal compartment syndrome. Thoracoabdominal compartment syndrome is described as transmission of abdominal pressure through a defective diaphragm causing compression of the hemithorax viscera and mediastinal shift with a hemodynamic alteration. The association of these anomalies is rare, and the possibility of this finding in a patient with eventration should always be considered.

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ABSTRACT The authors describe a rare unilateral muscle variation in the thoracic wall combining the pectoralis quartus and chondro-epitrochlearis muscles. A routine dissection was performed in the upper right limb of a male adult cadaver with approximately 35-50 years of age, embalmed in formalin 10%. An accessory muscle, the pectoralis quartus, was identified and was associated with a tendon that was inserted in the medial humeral epicondyle, characteristic of the chondro-epitrochlearis muscle tendon. Such variations have significant clinical relevance to orthopedics, mastology, neural and vascular surgery, and other specialties, for surgical approaches in both the axillary and brachial regions.

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ABSTRACT Spinal muscular atrophy (SMA) is a heritable neuromuscular disorder which encompasses a large group of genetic disorders characterized by slowly progressive degeneration of lower motor neurons. The mutation is seen in the SMN1 gene mapped on chromosome 5. Depending on the age of the onset and the degree of severity, SMA has three subtypes. We discuss the autopsy findings in a case of Type 1 SMA also known by the name Werdnig-Hoffmann disease, to highlight the primary changes in the spinal cord, and skeletal muscle with association changes in the liver and terminal respiratory complications.

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ABSTRACT Peripheral neuropathy is common, but rarely due to vasculitis. This report is the case of a 74-year-old woman with systemic vasculitis who presented with progressive arm and leg weakness associated with numbness. Autopsy revealed a colon cancer, which may have triggered the vasculitis. This case illustrates the association between vasculitis and malignancy. The best treatment of vasculitis in patients with cancer-associated vasculitis is usually treatment of the cancer, which often yields remission of the vasculitis. This case also illustrates the difficulty of suspecting vasculitis since the symptoms and signs are nonspecific and protean. It is important not to miss a diagnosis of vasculitis. It is often life-threatening. It is treatable. The critical step in the diagnosis of vasculitis is to think of it.

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ABSTRACT Primary non-Hodgkin lymphoma of the bone (PLB) is a rare type of non-Hodgkin’s lymphoma (NHL) that affects the skeletal system with or without regional lymph node involvement. We present the case of a 74-year-old female patient with pain due to multifocal osteolytic lesions. The diagnosis of diffuse large B-cells (non-GCB) phenotype was made by clinical, laboratory, histopathological examination accompanied by an extensive immunohistochemical profile of one of the skeletal lesions.

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ABSTRACT Long term use of D-penicillamine for Wilson’s disease can be associated with many adverse reactions and systemic side effects. We report the case of a 28-year-old male patient diagnosed with Wilson's disease presenting with a serpiginous raised violaceous skin lesion in the anterior aspect of the neck over the last six months and two small papules with central umbilication during the last month. Histopathological examination of skin lesions demonstrated transepidermal perforating channel, and the Verhoeff's-van Gieson stain showed marked increase number of irregular serrated elastic fibers suggesting the diagnosis of D- penicillamine induced elastosis perforans serpiginosa.

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ABSTRACT Histiocytic sarcoma (HS) is a rare hematolymphoid malignant neoplasm with an aggressive clinical course. It can arise de novo or from low-grade B-cell lymphoma. We describe the case of a 16-year-old boy referred to our hospital with generalized lymphadenopathy, weight loss, and decreased appetite for one month. The patient died undiagnosed on the 7th day of hospitalization. Lymph node and bone marrow biopsies were performed one day before the patient died. The lymph node biopsy revealed an architectural effacement with a diffuse proliferation of large pleomorphic neoplastic cells containing large, multilobulated nuclei, coarse vesicular chromatin, prominent nucleoli, and a moderate amount of eosinophilic cytoplasm. The bone marrow aspiration smears and biopsy also showed evidence of infiltration by these above-mentioned cells. Based on the morphology, along with the exclusion of many differential diagnoses by an extensive panel of immunohistochemical markers, a diagnosis of HS was made. This case report aims at evaluating all the clinical and immunophenotypic features of a case of HS with multifocal presentation and an aggressive clinical course in order to give a correct and definite diagnosis at the proper time.

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ABSTRACT In adults, B-lymphocytes comprise approximately 10% of circulating lymphocytes. The majority of peripheral B cells are B2 cells (“Mature” B-cells), which function as part of the humoral adaptive immune system. B1 cells (“Innate-like” B cells) are another sub-class of B lymphocytes, considered as innate immune cells with a characteristic phenotype (CD20+, CD27+, CD43+, CD70-, CD11b+, sIgM++, sIgD+) which can be divided into two subtypes; B1a (CD5+): spontaneously produce broadly reactive natural IgM, and B1b (CD5-): can generate T-cell independent, long-lasting IgM. There is very limited data available, indicating a correlation between allogeneic bone marrow transplantation and an increase in B1a cells. Here we present a case of a 17-year-old female with homozygous sickle cell disease (HbSS disease) who underwent hematopoietic stem cell transplant (HSCT). Approximately seven months post-transplant, she was found to have 16% immature mononuclear cells on complete blood count (CBC)-differential report. A follow-up peripheral blood flow cytometry showed that these cells were polyclonal CD5+/CD20+ B-cells, and comprised 66% of lymphocytes. Further workup and follow up failed to reveal any lymphoproliferative disorders. It is important not to misdiagnose these cells as an atypical CD5+ lymphoproliferative disorder. The presence of B1a cells has not been widely reported in non-neoplastic post-stem cell transplanted patients. This case also adds to and expands our knowledge regarding the presence of increased circulating B1a cells after stem cell transplant in a patient with no history of hematological malignancy.

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ABSTRACT Giant cell reparative granuloma (GCRG) was first described in the 1950s. It is an uncommon and benign reactive tumor that is believed to occur after trauma or inflammation. It most commonly occurs in the maxilla and mandible and rarely affects the nasal cavity. It is often seen in children and during the second to third decades of life, predominantly seen among females. Histopathologically, GCRG shows many osteoclast-like multinucleated giant cells scattered in a background of mononuclear stromal cells and spindle-shaped fibroblasts also associated with areas of hemorrhage. The distinction between GCRG and giant cell tumors (GCT)is crucial since both have a similar clinical and histological presentation, but both have different management. GCTs have malignant potential, may metastasize, and have a high rate of recurrence. Surgical excision is the mainstay therapy of GCRG to ensure a low rate of recurrence. Here we discuss two cases GCRG, both presenting as nasal mass.

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Abstract Leukemic cells are rarely present in the oral cavity, and there are very few reports regarding such cases. However, we identified some reports of leukemic cells infiltrating tissues in the oral cavity, including gingival involvement. Recurrent painful oral ulcerations and prominent generalized periodontal destruction are the most common oral features of neutrophil disorders, and they may even be the initial symptoms of the disease. The ulcers may affect any part of the oral mucosa, including the tongue and palate. The objective of this report is to describe and discuss a case of myeloid sarcoma in the oral cavity of a 48-year-old male patient.

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ABSTRACT Hyalinizing clear cell carcinoma (HCCC), also known as clear cell carcinoma, not otherwise specified [CCC, (NOS)], is a rare minor salivary gland tumor characterized by proliferation of clear cells, organized in trabecular cords, or solid nests within loose to densely hyalinized stroma. It is considered a diagnosis of exclusion by the World Health Organization (WHO) because other salivary tumors may also have a clear cell component. Hence, there is a wide differential diagnosis. EWSR1-ATF1 gene rearrangements are fairly specific for this tumor, however, one of the recent studies have described its presence in clear cell odontogenic carcinoma (CCOC) one of its histologic mimickers. EWSR1 and CREM fusions have recently been described in these tumors but its importance is still not well described. Here we present a case of a 33-year-old woman who presented with a recurrent lesion of the soft palate. Her initial lesion was resected and diagnosed as low-grade myoepithelial tumor. Surgical margins at the time of initial resection were positive and the re-excision was recommended but the patient did not undergo surgery. Two years later, local recurrence at the same site was found and an excision was performed yielding negative margins. Histopathologic examination revealed features consistent with hyalinizing clear cell carcinoma. The patient remains disease free 1 year after the re-excision. The pathology, clinical characteristics, differential diagnosis and treatment of hyalinizing clear cell carcinoma are reviewed.

Resumo em Inglês:

ABSTRACT Emphysematous gastritis (EG) is a rare and potentially lethal process caused by invasive, gas-producing bacteria leading to inflammation and gas dissection of the stomach. The most common etiologic agents are Clostridium infections, but other organisms, including enterobacteria, staphylococcus, and fungi have also been identified. We report the first case of EG due to Sarcina ventriculi in a solid organ transplant recipient, who presented with epigastric pain and vomiting. The patient had a history of type 1 diabetes mellitus (DM) with recurrent episodes of ketoacidosis and systemic diabetic complications, including severe gastroparesis. CT scan studies demonstrated EG with venous air, and endoscopy showed severe gastritis and ulcerations. In the gastric biopsies, abundant Sarcina ventriculi were noted in areas of mucosal/submucosal necrosis. Antibiotic treatment was instituted at admission, and subsequent endoscopy demonstrated the disappearance of Sarcina, with some improvement of the gastric inflammation; however, the patient developed septic shock with multiorgan failure and expired. This case highlights the need to consider other infectious etiologies in transplant patients, in addition to the well-known opportunistic infections.

Resumo em Inglês:

ABSTRACT Compressive syndromes of peripheral nerves both in the upper and lower limbs are part of daily clinical practice; however, the etiological diagnosis can be challenging and impact on the outcome of the patient. We report five cases with rare etiologies of nerve entrapments: one in the lower limb and four in the upper limbs with the final diagnosis made only during the operation. The patients evolved without post-operative complications and had good outcomes. This series includes the first report of sciatic compression by a lipoma in the popliteal fossa, two lipomas one with compression of infraclavicular brachial plexus and another with compressing the posterior interosseous nerve, and two reports of vascular lesions due to blunt traumas, which are also uncommon. This series adds to the literature more hypotheses of differential diagnoses in nerve entrapments, which is fundamental to surgical decisions and pre-operative planning—and perhaps most importantly prevents wrong diagnosis of idiopathic compressions, which would lead to a completely wrong approach and unfavorable outcomes.