Twin Fetus-in-Fetu: The Story of an Encaged Twin.

Background: Fetus-in-fetu (FIF) features a monozygotic, diamniotic, parasitic twin enclosed within its host twin. Case report: An 11-month baby girl presented with an antenatal diagnosis of a retroperitoneal mass. Radiological findings suggested it to be a teratoma. The mass was excised in-toto, histological findings were consistent with fetus-in-fetu. Conclusions: FIF may not have identifiable vertebral bodies and limbs upon imaging. Organized organ systems help differentiate this from a teratoma.

A Case of Medullary Carcinoma of Colon Morphologically Resembling Non-Hodgkin's Lymphoma.

Medullary carcinoma of the colon is an unusual and unique histologic subtype of colorectal cancer. It is strongly associated with microsatellite instability, most commonly loss of MLH1 indicative of deficient mismatch repair proteins. Diagnosis is challenging as they do not display the usual histological pattern. Immunohistochemical staining also shows unusual findings like negativity for CD20 and CDX2. Here, we explore an intriguing case of medullary carcinoma of colon which showed loss of MSH2 and MSH6 and a morphology reminiscent of Non-Hodgkin's lymphoma.

Xeroderma Pigmentosum with a Rapidly Proliferating Squamous Cell Carcinoma in a 4-Year Old Kid: A Rare Entity in Indian Subcontinent.

Xeroderma pigmentosum is a rare autosomal recessive genetic disorder, affecting nucleotide excision repair against ultraviolet radiation. This genodermatosis (a hereditary skin disorder) is distinguished by photosensitivity, alterations in cutaneous pigmentation, premature aging of the skin, and the typically observed onset of cutaneous and internal malignancies towards the conclusion of the first decade of life. In this article, we present a case involving a 4-year-old girl from North India who was born to non-consanguineous parents and developed an extensive fungating growth on her face. Subsequent diagnosis revealed the presence of squamous cell carcinoma, resulting in significant facial disfigurement. While xeroderma pigmentosum is a recognized condition, its occurrence in India, particularly in the northern region, is relatively rare. This report also underscores a noteworthy observation-the emergence of a cutaneous malignancy at such a tender age.

Myxoid liposarcoma diagnosed on fine needle aspiration cytology: There is more to it than meets the eye.

ABSTRACT: Liposarcoma is a rare mesenchymal neoplasm commonly involving deep soft tissues and the retroperitoneum. Among the various types of liposarcoma, myxoid liposarcoma is the most frequently encountered in adolescents and young adults, with a predilection for lower extremities. Fine needle aspiration allows easy assessment and rapid on-site evaluation for distinguishing benign from malignant lipomatous lesions. Here, we present a case of myxoid liposarcoma in the calf region of a 19-year-old boy, diagnosed via fine needle aspiration cytology, and subsequently confirmed by histopathological examination after surgical resection. The intention behind this case report is to highlight the cytological features of myxoid liposarcoma and to improve understanding of this tumor entity, aiming to prevent misdiagnosis by inexperienced pathologists when evaluating cytology specimens.

Spontaneous Tumor Lysis Syndrome in a Case of Hepatocellular Carcinoma with Sarcomatoid Differentiation.

Sarcomatoid hepatocellular carcinoma is a rare histologic variant of primary liver cancer comprising of malignant spindle cells and typical hepatocellular carcinoma (HCC). In terms of clinical presentation, they usually exhibit extensive tumor burden due to their larger size and a metastatic disease at the time of diagnosis as compared to conventional HCC. Tumor lysis syndrome is an oncological emergency, usually seen after cytotoxic chemotherapy in haematological malignancies. Here, we highlight a case of 76-year old male with no comorbidities, presenting with an excruciating backache and a paravertebral soft tissue mass and multiple osteolytic lesions, was clinically suspected to be a plasma cell neoplasm. On further evaluation, the patient was diagnosed of a sarcomatoid variant of hepatocellular carcinoma. This report showcases multiple rare findings by the presence of non-specific symptoms, non-cirrhotic liver, normal serum alpha protein levels and the occurrence of a spontaneous tumor lysis syndrome in a solid malignancy.

Benign Lesion of the Common Bile Duct Mimicking a Malignant Tumor: an Entity Commonly Overdiagnosed Clinically.

Adenomyomatous hyperplasia and adenomyoma are rare benign inflammatory pseudotumors of the gallbladder arising from Rokitansky-Aschoff sinuses. Occurrence of these hyperplastic conditions in the Vaterian and biliary system is extremely rare and is a concern for gastroenterologists and surgeons in distinguishing them from primary malignancies of the biliary system. Definitive diagnosis by imaging or cytopathological examination is difficult; thus, surgical resection becomes the only choice in such cases to relieve the obstruction. Here, we report two extremely rare cases of adenomyomatous hyperplasia of the extrahepatic bile duct after an extensive diagnostic workup, followed by Whipple's procedure.

A nuanced exploration delving into malignant melanomas occurring in unexpected and less common anatomical locations.

Malignant melanoma originates from melanoma cells, which derive from the neuroectoderm of the ectodermal mucosa. The chameleonic presentation of malignant melanoma, its often asymptomatic nature, the rarity of the lesion, the grim prognosis, and the imperative for highly specialized treatment are critical factors that merit careful consideration. Herein, we report a compilation of five cases of malignant melanomas occurring at unusual anatomical locations, which were initially misdiagnosed, which on careful analysis with the use of immuno-histochemical stains were correctly diagnosed as malignant melanoma.

An Unusual Case of Metastasis to Bilateral Breasts Masquerading as Disseminated Tuberculosis in a 17-Year-Old Girl with Quadriplegia-Where Is the Primary? An Unsolved Mystery.

Invasive breast cancer, no special type, is the most frequent subtype of breast malignancy encountered as compared to secondary breast cancer. The most common tumors metastasizing to the breast include lymphoma and melanoma. Rhabdomyosarcoma (RMS) is a common soft-tissue neoplasm in the paediatric population, often seen in regions such as the head and neck, genitourinary system, trunk, and extremities. While metastatic RMS to the breast is uncommon, it tends to occur primarily in adolescent girls, with the alveolar variant being the most frequently encountered. In this case presentation, we describe the unique instance of a 17-year-old girl admitted to the hospital with quadriplegia which on initial clinical evaluation was diagnosed as disseminated tuberculosis involving the spine (Pott's spine), but on further cytologic and histopathologic assessment revealed the unexpected diagnosis of rhabdomyosarcoma. This case draws attention to the unusual occurrence of rhabdomyosarcoma metastasis to bilateral breasts, that to with an embryonal morphology, and underscores the challenge of identifying the primary site of this rare manifestation.

Shining Light on Rarity: Mucoepidermoid Carcinoma of the Esophagus with Absence of MAML2 Gene Rearrangement.

Primary mucoepidermoid carcinoma of the esophagus is a rare condition characterized by a combination of squamous and mucin-secreting glandular malignant cells. Its clinical recognition is often challenging, pre-operative diagnosis is difficult, and there is a lack of standardized treatment protocols. Here, we present the clinicopathological characteristics of a previously underreported esophageal malignancy found in the distal esophagus of a 58-year-old woman. The initial endoscopic biopsy posed diagnostic challenges due to its small size and inadequate representation of glandular differentiation components making a final diagnosis of poorly differentiated squamous cell carcinoma. Recognizing the resectability of the tumor prompted surgical removal, revealing islands of squamous cells along with intermediate cells and mucin pools. Additionally, MECs in majority of the cases show MAML2 gene rearrangement; contrarily, the present case showed negative results. Enhanced clinicopathological awareness of esophageal MEC facilitated a definitive diagnosis and better patient management. It is imperative to increase awareness and globally document cases of esophageal MEC to enhance understanding, diagnosis, and management guidelines for this malignancy in this anatomical location.

Beyond Bones: Exploring Primitive Neuroectodermal Tumor of Kidney.

A primitive neuroectodermal tumor (PNET), classified as a malignancy of the Ewing's sarcoma family of tumors, is typically observed in bones or soft tissue among adolescents and young adults. However, its occurrence outside the skeletal system (extra-osseous location), particularly within visceral organs, is infrequent. Renal PNET is exceptionally uncommon and exhibits an exceedingly aggressive biological behavior, leading to a dismal prognosis as compared to conventional renal cell carcinoma. In this report, we present the case of a 28-year-old adult male patient diagnosed with renal PNET on ultrasound-guided biopsy, who initially presented with left flank pain and recent onset of hematuria within a brief timeframe. Left radical nephrectomy followed by postoperative VDC-IE (combined vincristine, doxorubicin, and cyclophosphamide followed by another combination of ifosfamide and etoposide) chemotherapy was given to the patient. This case serves as a reminder to nephrologists, medical oncologists, and pathologists that in adolescents and young adults presenting with suspicious renal masses, a diagnosis of renal PNET should always be considered. Timely surgical intervention, coupled with chemotherapy, is essential for optimal therapeutic management and improved prognosis in cases of such rare and aggressive malignancies.

Adult-Onset Neuropsychiatric Symptoms as the Presenting Feature of Xeroderma Pigmentosum Group G: A Report of a Rare Case.

Xeroderma pigmentosum is a rare autosomal recessive disorder resulting in heightened cutaneous photosensitivity due to aberrant DNA repair mechanisms. Early-life developmental delay and cognitive impairment have been described in xeroderma pigmentosum cases. However, psychiatric symptoms in adulthood as the presenting feature of xeroderma pigmentosum have not been reported. We report a young adult with xeroderma pigmentosum group G presenting with prominent neuropsychiatric manifestations and evidence of neurodegeneration. The clinical, laboratory, and radiological findings, skin biopsy, and the results of the genetic testing of the patient have been described after obtaining written and informed consent. A young adult male with skin photosensitivity since infancy developed hyper-religiosity, delusions, suicidal ideations, speech hypernasality, lower limb spasticity, and cognitive impairment over the past four years. The MRI of the brain showed diffuse cerebral atrophy. The skin biopsy from bilateral cheeks showed evidence of flattening and thinning of rete ridges, pigment incontinence, and perivascular and periappendageal inflammatory infiltrate. The whole exome sequencing in ethylenediaminetetraacetic acid (EDTA) blood revealed a compound heterozygous likely pathogenic mutation in intron 13 (c.2880-2A>G (3' splice site)) and a mutation in exon 15 (c.3146del (p.Asp1049ValfsTer12)) in the ERCC5 gene suggestive of xeroderma pigmentosum group G. This case highlights that prominent neuropsychiatric features in adulthood can occur due to xeroderma pigmentosum. Thus, xeroderma pigmentosum group G should be considered as a possibility among young adults presenting with neuropsychiatric features, evidence of neurodegeneration, and early-life skin photosensitivity.

Gastric Metastasis of Primary Neuroendocrine Tumor of Skin: Rare Tumor with Rare Presentation.

Merkel cell carcinoma (MCC) is a rare primary neuroendocrine tumor of the skin. It has an aggressive biological behavior and shows early local and distant metastasis. Diagnosis of MCC is a challenge and requires confirmation by immunohistochemistry (IHC). However, metastasis of MCC to the stomach is extremely uncommon and is rarely reported in the literature. We hereby describe a patient with gastric metastasis of MCC, who presented with black tarry stool and was finally diagnosed on the basis of clinical history, histology, and IHC.

Anaplastic (undifferentiated) carcinoma of pancreas, an uncommon variant: Diagnosed on endoscopic-guided fine needle aspiration.

Anaplastic carcinoma of pancreas (ACP) are rare pancreatic neoplasms. They are well known to be associated with more aggressive tumor behavior and less favorable prognosis than usual pancreatic ductal adenocarcinoma. Endoscopic-guided fine needle aspiration (EUS-FNA) is now a widely accepted modality in diagnosis of pancreatic lesions. However, only a few reports are available describing cytological features of anaplastic carcinoma. Here, we report two cases of ACP diagnosed on EUS-FNA.

Liver abscesses caused by visceral larva migrans: Aimless wanderer separated from the host.

Visceral larva migrans (VLM) is a systemic zoonotic parasitic disease caused by migration of the second stage larva through viscera of humans. Despite being a foremost public health problem in low- and middle-income countries (LMICs) such as India, larva migrans remains an untended zoonosis. Here, we report two cases of VLM who presented with fever and abdominal pain for a prolonged duration. On further investigation, marked peripheral eosinophilia with multiple confluent necrotizing eosinophilic granulomas were identified on histopathological examination of the liver.

Concomitant Langerhans and Interdigitating Reticulum Cell Hyperplasia in a Reactive Lymph Node of an Infant with Omenn Syndrome: A Diagnostic Pitfall for Langerhans Cell Histiocytosis.

Omenn syndrome, a rare form of combined immunodeficiency in infants, presenting with recurrent infections, erythroderma, lymphadenopathy, hepatosplenomegaly, eosinophilia, and increased serum IgE levels. It is a fatal condition unless treated by hematopoietic stem cell transplant. Hence, an early diagnosis and a prompt treatment can lead to better outcome in these unfortunate babies afflicted with Omenn syndrome. Here, we present an 8-week-old infant with typical features of Omenn syndrome, both clinically as well as on laboratory analysis, but surprising immunohistochemical findings on lymph node biopsy.

Cystic Pancreatic Neuroendocrine Tumor: A Diagnostic Dilemma.

Pancreatic neuroendocrine tumors are typically solid neoplasms but in rare instances may present as cystic lesions. Preoperative diagnosis of a cystic pancreatic lesion is challenging and requires a multidisciplinary and multimodal approach. We hereby describe an elderly female who came with complaints of abdominal lump. Radiologically, it appeared to be a pancreatic hydatid cyst located at the head of the pancreas, following which resection was done. Histopathological study of the lesion turned out to be a cystic pancreatic neuroendocrine tumor. Thus, we present this unique case due to its rarity and diagnostic challenge.

Amelanotic Melanoma: A Great Masquerader.

Malignant melanoma is an aggressive, notorious tumor showing great variability in morphological and immunohistochemical expression, thus commonly leading to an erroneous diagnosis. Within the melanoma group, amelanotic melanoma, with its wide clinical presentations, lack of pigmentation, and varied histological appearances, has taken on a new persona as a master masquerader. Use of immunohistochemistry in the diagnosis of malignant tumors, including melanoma, is primordial and indispensable. However, the problem gets compounded in scenario of aberrant antigenic expression. The present case posed multiple diagnostic challenges in form of atypical clinical presentation, variant morphology, as well as aberrant antigenic expression. Here, we present the case of a 72-year-old male who, upon his initial presentation, was thought to be sarcomatoid anaplastic plasmacytoma, but 5 months later another biopsy from a different site revealed the actual diagnosis of amelanotic melanoma.

Acantholytic Squamous Cell Carcinoma: a Diagnostic Pitfall on Cytology.

Acantholytic squamous cell carcinoma is an infrequent subtype of squamous cell carcinoma. This tumour variant being rare in itself has been rarely described at the penile location, thus leading to a limitation on information of pathological and immunohistochemical findings and prognosis. Clinical observations indicate an aggressive biologic behaviour. The cytological features on fine-needle aspiration cytology samples have rarely been described in literature. It is imperative for pathologists to be aware of the cytological features so as to allow the distinction of this variant from conventional squamous carcinoma. Here, we explore an intriguing case of a metastatic tumour to inguinal lymph node with the primary lesion at the penis which constituted a diagnostic challenge on cytological examination.

Transformation of ameloblastoma to ameloblastic carcinoma in a 10-year-old child.

Ameloblastic carcinoma (AC) is a rare odontogenic malignant epithelial neoplasm of maxillofacial skeleton with a distinct predisposition of the mandible. It can occur in a wide range of age groups, with a sex predilection in males. It can arise either as a de novo lesion or from preexisting ameloblastoma. AC has a high propensity for local recurrence as well as distant metastasis (chiefly lungs), thus requiring an aggressive surgical approach and a strict surveillance. Owing to the rarity of publications describing AC, little is known about this entity in pediatric patients. We report a case of transformation of ameloblastoma into AC in a 10-year-old child.

Synchronous Malignancies: Pathological Analysis of Three Patients, Each with Dual Malignancies.

Multiple primary malignancies are defined as two or more malignancies arising independently to each other in the same or different anatomical sites, while excluding the possibility of metastasis from the primary malignancy. Here, we present three cases, each with dual malignancies involving different anatomical locations.