P63-expressing Prostate Adenocarcinoma: A Case Study of a Rare Subtype

Introduction/Objective

Prostate acinar adenocarcinoma (PCa) is a well-researched,and often diagnosed entity. A combination of architectural and cytologic characteristics are used in accurately identifying these carcinomas. However, the diagnosis can be challenging when the foci are minute or the cancer presents with unusual features. Ancillary studies aid in these scenarios. The loss of basal cells in adenocarcinoma makes markers targeting these cells desirable. PIN4 cocktail immunohistochemical stain, which combines alpha-methylacyl-coA racemase (AMACR), that is overexpressed in prostate carcinoma, with basal markers high molecular weight cytokeratin and p63, is a popular ancillary study to assist diagnosing demanding cases. Herein, we present a rare, challenging subtype of prostate carcinoma expressing p63.

Methods/Case Report

A 66-year-old male, with a past medical history of treated HIV and hyperlipidemia, underwent screening biopsies for a PSA of 7.5 ng/mL. Out of 22 parts, three cores showed modest amounts of atypical infiltrating cells. The architecture comprised of ill-defined glands, individual cells and single files of cells. They possessed high nucleocytoplasmic ratio giving a hint of atrophy, with occasional spindling and prominent nucleoli. To add to the challenge, PIN4 immunostaining showed strong nuclear expression of a basal marker with negative AMACR. Due to unusual morphology and basal marker expression, a consideration of basal cell lesion was entertained. However, subsequent staining revealed negative expression of HMWCK, and positive expressions of NKX3.1 and p40. Overall, with this morphology and immunoprofile we diagnosed our case as prostate carcinoma with aberrant expression of p63.

Results (if a Case Study enter NA)

N/A

Conclusion

Grading these lesions is controversial as they are considered to carry a better prognosis over conventional acinar adenocarcinoma of similar grade. A distinct etiopathology is suspected as molecular tests for ERG and PTEN are without alterations. Further discussion and characterization of these lesions is warranted as they are infrequently encountered and prone to being overlooked due to their similarities to benign basal cells.

Primary S100 Negative Amelanotic Spindle Vaginal Melanoma

Introduction/Objective

Vaginal melanoma is a rare malignancy composed of cells showing melanocytic differentiation and represents less than 3% of malignant vaginal tumors. It occurs in older women, typically in the distal third of the vagina. Outcomes are poor and median survival is less than 2 years. Macroscopically, 90% of these lesions are pigmented, polypoid and ulcerated. Microscopically they demonstrate diffuse, nested, trabecular, and/or fascicular patterns and are comprised of epithelioid cells with or without a spindle cell component. They are typically pigmented and S100 positive.

Methods/Case Report

Here we present a rare case of purely spindled amelanotic S100 negative vaginal melanoma. The patient is a 75 year old woman who presented with a 6 month history of vaginal discharge, and a one month history of new foul odor and vaginal bleeding, constipation, and unintentional weight loss. A large vaginal mass was palpated on physical exam. Subsequent computed tomography demonstrated a 8.2 x 8.2 x 9.4 cm mass occupying the vaginal vault with abutment of the urinary bladder anteriorly and the rectal and anal walls posteriorly. A biopsy was performed and a 3.8 x 2.2 x 1.2 cm aggregate of pink tan friable tissuse was obtained. Histopathologic examination showed a malignant neoplasm composed purely of spindled cells in a fasicular pattern. Tumor cells showed marked nuclear pleomorphism with inconspicuous nucleoli. Tumor necrosis was present. No pigment was seen. By immunohistochemistry, tumor was positive for SOX10, HMB45, and Melan A, and negative for S100, AE1/3, EMA, myogenin, desmin, smooth muscle actin, synaptophysin, chromogranin, Pax8, and GATA3. BRAF mutation analysis showed no mutations. Patient received radiation therapy with a good clinical reponse.

Results (if a Case Study enter NA)

NA.

Conclusion

Amelanotic S100 negative spindled vaginal melanoma is an unusual presenation of a rare tumor and should be considered in the workup of malignant vaginal tumors with a spindle cell morphology.

Rhabdoid Melanoma Solitary Metastasis to Kidney with Renal Vein Invasion Mimicking Renal Cell Carcinoma

Introduction/Objective

83 percent of malignant melanoma cases present as localized skin lesions. However, a small percentage of patients present with concurrent metastatic disease or experience late metastasis. Metastatic melanoma has highly variable presentation and morphology, frequently mimicking other tumors. The most common metastatic sites in order of frequency are skin and subcutaneous tissue, lungs, liver, bones, and brain. While rare, metastasis to the kidney can occur and typically takes the form of multiple micrometastases.

Methods/Case Report

Here we present an unusual case of a late, purely rhabdoid large solitary renal metastatic melanoma with renal vein invasion, mimicking rhabdoid renal cell carcinoma. The patient is an 84 year old male with a remote history (30 years) of cutaneous malignant melanoma who was referred with a CT scan demonstrating 7.9 x 5.7 x 5.7 mass in the lower pole of the left kidney with a tumor thrombus in the renal vein hhighly suspicious radiographically for renal cell carcinoma. The patient underwent a radical nephrectomy. Macroscopically there was a solitary 7.7 x 6.3 x 5.5 cm tan-grey mass in the lower pole with gross invasion into the renal sinus fat and renal vein resembling the macroscopic appearance of a renal cell carcinoma. Microscopic examination demonstrated pleomorphic tumor cells with pure rhabdoid morphology, extensive necrosis and Lymphovascular invasion. No pigment was identified. No classic clear cell areas were identified. Immunohistochemical stains were positive for S100, SOX10 Melan-A, HMB45 and vimentin and negative for AE1/3, CK7, CAIX, PAX8, P63, CD117 and AMACR. Multiple resected lymph nodes were negative for metastasis

Results (if a Case Study enter NA)

NA.

Conclusion

This case is a rare and unusual presentation of melanoma, and it’s important to keep this diagnosis in consideration in the setting of unusual morphology of renal tumors.

Malignant Glomus Tumor of the Kidney: A Case Report and Review of the Literature

Introduction/Objective

Glomus tumors are rare neoplasms arising from the glomus body which is a specialized arteriovenous anastomosis that has a role in temperature regulation of the skin. They account for less than 2% of soft tissue tumors and typically manifest as painful nodules in the extremities, most commonly in the subungual region of the fingers and dermis of the wrist, forearm, and foot. They rarely arise in visceral organs as they lack glomus bodies. There are rare case reports of benign glomus tumors arising in the kidney, and malignant renal glomus tumors are exceedingly rare.

Methods/Case Report

We present a case of a 32-year-old man who was found to have a right renal mass incidentally after being involved in a motor vehicle accident. Computed tomography of the abdomen revealed a 5.3 cm enhancing mass in the posterior aspect of the inferior pole of the right kidney. Histological examination revealed a solid neoplasm composed of a pleomorphic population of cells with densely eosinophilic to pale cytoplasm, centrally located round to oval nuclei with fine nuclear chromatin and relatively inconspicuous nucleoli. Prominent lymphovascular invasion and 1 mitotic figure per 10 high power fields were also present. Areas composed of necrosis, sclerosis, hemosiderin deposition and calcification were identified. Immunohistochemical stains revealed the neoplastic cells to be positive for CD34, vimentin, smooth muscle actin, caldesmon, with focal reticulin staining around the tumor cells. Cells were negative for desmin, high and low molecular weight cytokeratins, synaptophysin, chromogranin, PAX8, and GATA3. The morphology and immunoprofile of the mass are consistent with the diagnosis of glomus tumor.

Results (if a Case Study enter NA)

NA

Conclusion

Although very rare, the presence of prominent vascular invasion, increased mitotic activity as well as necrosis are consistent with malignant behavior and support the classification as a malignant glomus tumor.