Penile Myointimoma in Children and Adolescents: A Clinicopathologic Study of 5 Cases Supporting a Distinct Entity

Myointimoma (angiocentric myofibroblastic tumor) of the glans penis in an adolescent: a case report and review of the literature

Background

Soft tumors of the penis are extremely rare in childhood and adolescence. Because there are no guidelines, each such case raises embarrassment over the extent and degree of aggressiveness of the diagnostic and therapeutic procedures. Herein, we describe a case of a teenager with a penile myointimoma along with a review of the literature. So far, only 10 cases have been reported in this age group.

Case presentation

The 15-year-old boy presented with a 6-months history of a slowly growing, palpable firm nodule in glans penis. Physical examination revealed a palpable, well circumscribed, firm, whitish painless mass, around 1 cm in diameter within the glans. Ultrasound revealed hypoechogenic, hypoperfused poorly defined area inside the glans. MRI did not confirm any other pathologic mass inside the glans and corpora cavernosa. An excisional biopsy was performed; its immunohistological features indicated myointimoma.

Discussion and conclusion

Given the rarity of this benign entity, the main importance is to distinguish myointioma from more clinically aggressive neoplasms. The key to a correct diagnosis is a careful histological examination, including immunohistochemistry. Local excision is safe and effective treatment modality.

Penile Myointimoma: A Clinicopathologic Study of 4 Tumors

Penile myointimoma is a rare, benign tumor occurring within the corpus spongiosum vasculature of the glans penis. Thus far, there have been twenty-three reported tumors in the literature. We present four additional tumors of this unique myointimal proliferation. Patients ranged in age from 20 to 68 years and presented with a firm mass on the glans penis. All four tumors displayed distinctive morphologic features consisting of a myointimal proliferation with plexiform architecture of bland myofibroblastic cells in a myxoid background in the corpus spongiosum vasculature. Characteristic cytoplasmic immunoreactivity of lesional cells with smooth muscle actin in addition to a desmin positive collarette of native vessel smooth muscle was seen in all four tumors. No disease was reported in any of the patients at last clinical follow-up (9 months to 15 years) after biopsy or excision. Myointimoma is part of a rare group of mesenchymal tumors that has been recently classified by its distinctive location, morphology, and immunohistochemical reactivity. For any nodular, spindle cell lesion of the corpus spongiosum, myointimoma should be included in the differential diagnosis given its unique characteristics and favorable clinical outcome.

Peyronie disease: a clinicopathologic study of 71 cases with emphasis on histopathologic patterns and prevalent metaplastic ossification

Peyronie disease (PD) is a benign, superficial fibromatosis involving the fascial structures of the penis, causing deformity, pain, and loss of function, for which there are few contemporary studies of the histopathology. We performed a multi-institutional review of 74 routine and consultation specimens submitted with clinical concern for PD. Of these, three non-PD lesions were identified and excluded (a myointimoma, a mammary-type myofibroblastoma, and fibrocalcific atherosclerosis). Of the 71 confirmed to be PD, the majority of patients were white (83%), with a median age of 55 years (range: 26-88). The dorsal aspect of the penis was the most common site involved (78%), followed by lateral (12%) and ventral (10%) aspects. The median degree of curvature was 70° (range: 20-360°). On review, three overall histologic patterns characterized the lesions resected: dense fibrotic plaque (61%), dense fibrotic plaque with focal or patchy metaplastic ossification (35%), and plaque composed predominantly of metaplastic ossification (4%). The fibrotic component was predominantly nodular (18%), hyalinized/lamellar (46%), or mixed (32%), excepting two cases consisting entirely of metaplastic bone. Chronic inflammation, when present, was most often focal and perivascular in distribution. In one case, an excision after collagenase treatment showed myxoid change and increased stromal cellularity. Overall, these findings define the range of PD histology, particularly emphasizing that the calcification noted clinically nearly always represents bona fide metaplastic ossification. Such context will be of value in evaluating specimens prospectively, in light of changing practices and the use of new technologies for treatment.

Myointimoma of the penis

Myointimoma is an uncommon, benign soft-tissue tumor derived from the intimal cells of blood vessels. Since little is known about this rare tumor entity, our aim is to describe an additional case and to perform the first literature review on this topic. A 49-year-old Caucasian man presented with a 12-month history of a palpable, firm, solitary lesion involving the glans penis. On physical examination, there was a 1 cm palpable, endophytic well-circumscribed nodule located to the left side of glans penis, close to the coronal sulcus, with disease-free external urethral orifice. The patient was submitted to complete excisional biopsy. A skin rhombus measuring 1.1 × 0.8 × 0.3 cm was removed and the biopsy sample, fixed in 10% formaldehyde, sent to Pathology. At the 18-month follow-up visit, the patient was clinically disease free. Histopathology revealed a multinodular intravascular proliferation of the corpus spongiosum. This myointimal proliferation comprised bland predominantly spindle cells in an abundant fibromyxoid stroma. Immunostains for smooth muscle actin (1A4), cytokeratins (AE1/AE3, CAM5.2), and CD34 were carried out using the avidin-biotin complex (ABC) immunoperoxidase method. Lesional cells displayed positivity for smooth muscle actin and negativity for cytokeratins and CD34. Myointimoma is confirmed to be a penile benign lesion that may be adequately treated with excisional biopsy. Even after incomplete or marginal removal, the penile lesion has been shown to remain stable overtime or regress. Differential diagnosis is essential to exclude similar histologic entities that could be more aggressive or have possible systemic implications.

Benign Diseases and Neoplasms of the Penis

This article provides comprehensive review of benign diseases and neoplastic conditions of the penis. It describes and provides representative images of clinical, key pathologic features and ancillary techniques to aid in differential diagnoses. It examines these diseases from the epidemiologic standpoint, looks at environmental and genetic factors, and outlines the new histologic entities for penile neoplasms with distinct outcomes and clinical behavior that have been proposed in recent years.