INVERTED PAPILLOMA – Histopathology.guru

cINVERTED PAPILLOMA

Benign neoplasm comprising less than 1% of urothelial neoplasms
Male predominance is noted
Patient presents with gross or microcsopic hematuria
Size usually less than 3cms but rarely may grow upto 8cms
Cystoscopically – Inverted papillomas are solitary, raised, polypoidal or pedunculated lesion with smooth surface
Microscopy
- Cords of Urothelial cells invaginating into lamina propria showing peripheral palisading and with smooth borders
- Central portions of the cords contain maturing urothelial cells and surrounding tissue is stroma without stromal reaction
- Grows as expansile mass and do not infiltrate the muscular wall
- Rarely co-exist with carcinoma
- Cystic areas and foci of squamous metaplasia are common
- Neurendocrine differentiation is present in some cases
- Inverted papillomas exist in association with florid proliferation of Brunn nests
- Cellular atypia is common but true anaplasia is rare
- Atypical nuclear changes may result from compression of cells with in tightly packed trabeculae
Treatment and prognosis –
- complete transurethral resection is the treatment of choice
- Recurrence occurs in less than 1% of cases

References

William M.Murphy, David J.Grignon,Elizabeth J.Perlman. Tumors of urinary bladder. In: Tumors of the Kidney, Bladder, and Related Urinary structures. AFIP Atlas of Tumor Pathology Series 4;2004: 253-255.

Inverted papilloma: Lesion with endophytic growth. Tumor cells grow into stroma in the trabecular pattern (H&E,X50)

Inverted papilloma: Cords of tumor cells in the edematous stroma. Peripheral palisading of tumor cell nuclei is noted (H&E,X100)

Inverted papilloma: Cords of tumor cells in the edematous stroma. Peripheral palisading of tumor cell nuclei is noted Cyst lined by tumor cells is seen (right) (H&E,X100)

Inverted papilloma: Cords of tumor cells in the edematous stroma. Peripheral palisading of tumor cell nuclei is noted Cyst lined by tumor cells is seen (H&E,X100)

Inverted papilloma: Cords of tumor cells showing peripheral palisading of tumor cell nuclei. Nuclear atypia with hyperchromatism is noted (H&E,X400)

Inverted papilloma: Cords of tumor cells showing peripheral palisading of tumor cell nuclei. Nuclear atypia with hyperchromatism is noted. Centre of the cords show maturing transitional cells (H&E,X400)

Inverted papilloma: Cords of tumor cells showing peripheral palisading of tumor cell nuclei. Nuclear atypia with hyperchromatism is noted . Surface shows benign transitional epithelium (H&E,X400)

cINVERTED PAPILLOMA

Benign neoplasm comprising less than 1% of urothelial neoplasms

Male predominance is noted

Patient presents with gross or microcsopic hematuria

Size usually less than 3cms but rarely may grow upto 8cms

Cystoscopically – Inverted papillomas are solitary, raised, polypoidal or pedunculated lesion with smooth surface

Microscopy

Cords of Urothelial cells invaginating into lamina propria showing peripheral palisading and with smooth borders

Central portions of the cords contain maturing urothelial cells and surrounding tissue is stroma without stromal reaction

Grows as expansile mass and do not infiltrate the muscular wall

Rarely co-exist with carcinoma

Cystic areas and foci of squamous metaplasia are common

Neurendocrine differentiation is present in some cases

Inverted papillomas exist in association with florid proliferation of Brunn nests

Cellular atypia is common but true anaplasia is rare

Atypical nuclear changes may result from compression of cells with in tightly packed trabeculae

Treatment and prognosis –

complete transurethral resection is the treatment of choice

Recurrence occurs in less than 1% of cases

References

William M.Murphy, David J.Grignon,Elizabeth J.Perlman. Tumors of urinary bladder. In: Tumors of the Kidney, Bladder, and Related Urinary structures. AFIP Atlas of Tumor Pathology Series 4;2004: 253-255.