Opportunistic microsporidiosis unveiled by fine-needle aspiration cytology of cervical lymph node with literature review.

Microsporidia are highly specialized obligate intracellular organisms closely related to fungi, traditionally linked to diarrheal diseases in acquired immunodeficiency syndrome patients. Over the past two decades, an increasing incidence of extraintestinal infections affecting various organ systems, especially in immunocompromised individuals, has been observed. The report presents a unique case of lymph node microsporidiosis in a 38-year-old male, positive for human immunodeficiency virus, with coinfections of hepatitis B and C. Fine-needle aspiration cytology (FNAC) from cervical lymph node yielded pus-like, necrotic material with periodic acid-Schiff stained smear uncovering small round to oval spores on microscopy suspicious for microsporidia. Based on polymerase chain reaction and sequencing done with aspiration material, the causative agent was identified as Vittaforma corneae. This rare encounter highlights the significance of recognizing unique morphological characteristics of infectious organisms and employing appropriate ancillary techniques for precise identification. The case underscores the crucial role of FNAC in diagnosing opportunistic infections involving the lymph nodes and the growing significance of molecular tests for specific pathogen confirmation.

Bugs' eyes and black monsters: Ascitic fluid cytology in an elderly male with hematochezia.

Anorectal malignant melanomas are rare, accounting for less than 2% of all melanomas. Malignant effusions developing secondary to malignant melanoma are highly uncommon. Herein, we present the cytomorphological features of a metastatic anorectal malignant melanoma presenting with ascites at the initial clinical presentation.

Childhood pilomatrixoma mimicking malignant small round blue cell tumor with positivity for CD99: Potential pitfall in cytology.

Pilomatrixoma is a relatively rare benign skin appendageal tumor, often presenting in the pediatric age group as a nodular lesion and most commonly involving the head and neck, making it amenable to primary fine needle aspiration (FNA) diagnosis. We report the clinical and histopathological findings of two cases of pilomatrixoma in children, both of which were initially misdiagnosed as small round blue cell tumors due to high cellularity and misinterpretation of the proliferating basaloid cells. Histopathology revealed basal cell proliferation and mitoses indicating that they were progressive, early lesions. The first case showed membranous positivity for CD99 which prompted a diagnosis of Ewing sarcoma. Awareness of the morphological spectrum including positivity for CD99 and careful evaluation of cell block histology could have averted the misdiagnosis. Pilomatrixoma should be included as an important differential diagnosis when faced with primitive-appearing cells on FNA, especially in children with mass lesions in the head and neck region.

Cytomorphologic and immunocytochemical diagnosis of primary hepatic angiosarcoma in a young adult: Challenging diagnosis of a rare, aggressive malignancy.

Primary hepatic angiosarcoma (PHA) is a rare, rapidly growing, highly aggressive hepatic malignancy, primarily seen in elderly males. Establishing an accurate clinical diagnosis is challenging owing to its rarity and nonspecific presentation. Rendering a cytologic diagnosis of PHA is extremely difficult, and immunocytochemistry(ICC) on cell block(CB) sections is essential to confirm the diagnosis. The characteristic cytomorphologic features of PHA have rarely been documented, further augmenting the diagnostic challenge. A 32-year-old male presented with abdominal pain, abdominal distension, and significant weight loss over the past 9 months. On examination, the abdomen was distended, with multiple spider angiomas and a large mass in the right hypochondrium. His renal function tests, liver function tests, and serum tumor markers were within normal limits. An abdominal triphasic computerized tomography revealed a large lobulated mass in the right lobe with central necrosis. An ultrasound-guided FNA was performed from the liver lesion. The cytologic smears showed singly scattered large, markedly pleomorphic, epithelioid-elongated tumor cells having oval-elongated nuclei, irregular nuclear contours, coarse chromatin, prominent macronucleoli, and abundant finely vacuolated cytoplasm in a background of blood. ICC on the CB demonstrated diffuse positivity for vimentin, CD31, and nuclear positivity for FLI-1, confirming a vascular origin. Hence, a final cytologic diagnosis of primary hepatic angiosarcoma was rendered. The index report describes the characteristic cytomorphologic and immunocytochemical features of a rare hepatic malignancy in a young male and reiterates the usefulness of FNAC coupled with CB-ICC in the quick and precise diagnosis of such challenging cases.

Cytology coupled with immunocytochemistry identifies Merkel cell carcinoma: A rare intruder in the cerebrospinal fluid.

Merkel cell carcinoma is an uncommon aggressive skin tumour which is well known for its recurrence and metastasis. Leptomeningeal metastasis involving the cerebrospinal fluid is extremely rare. The diagnosis may easily be missed as it simulates other much more common small round blue cell tumours. A patient history with a primary diagnosis may not always be available. Awareness and cytomorphological vigilance with judicious employment of appropriate immunomarkers on limited cerebrospinal fluid samples is indispensable for reaching the correct diagnosis. The tumour cells are usually monotonous small round cells, singly scattered or arranged in loosely cohesive clusters. Cells have round to elongated nuclei with coarsely granular chromatin, nuclear moulding in places and scanty basophilic cytoplasm. A limited immunocytochemistry panel employing CK20 and CD56, for which the tumour is positive, is confirmatory. We herein present a case of infiltration of cerebrospinal fluid by Merkel cell carcinoma.

Facial Nerve Palsy with Total Ophthalmoplegia; a Novel Presentation of Fungal Invasion.

Mucormycosis is an expeditious invasion of a fungus of angioinvasive nature, predominant in immunocompromised individuals, often leading to organ malfunction and loss. Facial nerve involvement and total ophthalmoplegia are its rare presentations. Early detection and treatment can alter natural disease course and prevent potential catastrophic outcomes in diabetic patients. Facial nerve palsy is mostly attributed to peripheral neuropathy in patients with advanced diabetes mellitus. It rarely raises alarm about an invasive fungal infection. Here, we report the case of a 38-year-old male with type 2 diabetes mellitus, who presented to us with left lower motor neuron type facial palsy and left-sided total ophthalmoplegia due to invasive rhino-orbito-cerebral mucormycosis (ROCM). Despite aggressive measures, including antifungal therapy and repeated endoscopic debridement, he subsequently developed central retinal artery occlusion (CRAO) and underwent left eye exenteration.